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Census Population, 1970 - 2000

Summary This data set has counts of United States resident population by two 'by' variables: age (18 ranges), race (White ,Black , Amer. Indian/Alaskan Native , Asian/Pacific Islander, Unknown or missing ), gender, state and county of residence. The racial categories American Indian/Alaskan Native and Asian-Pacific Islander did not exist in Census data before 1990. Before 1990 these categories were included within the race category "Other". The ethnicity categories Hispanic/Non-Hispanic also did not exist in Census data before 1990. Caution should be exercised when making queries that include years both before and after 1990 and that display results by race or by Hispanic ethnicity.
Census years are 1970, 1980, 1990 and 2000. Data for the non-census years are projected.
Population The United States, 1970-2000
Source Bureau of the Census, Department Of Commerce.

Suggested Citation:   United States Department of Commerce, U.S. Census Bureau, Population Division; Census Population 1970-2000 for Public Health Research, CDC WONDER On-line Database, March 2003.

See Source Information for more details.
In WONDER You can produce tables, maps, charts, and data extracts. Request national, state and county bridged-race population estimates for the years 1990-2003. You can limit and index your data by any and all of these variables:
  1. Location - National, State and County (no territories).
  2. Year - 1970-2000.
  3. Race - American Indian or Alaska Native; Asian or Pacific Islander; Black or African American; Other, Unknown, or Missing; Multi-Racial; White.
  4. Ethnicity - Hispanic or Latino; Not Hispanic nor Latino; Unknown or Missing.
  5. Sex (Gender) - Female; Male.
  6. Age Group - age 0-4 years; 5 year age groups through age 84; age 85 and older.

Please refer to the following topics:

Bridged-race Population Estimates Data Request
Data Source Information
Additional Information

Census 1970-2000 Population Data Request

Output You can produce tables, maps, charts, and data extracts.

Variables
  1. Location - National, State and County (no territories)
  2. Year - 1970-2000
  3. Race - - American Indian or Alaska Native; Asian or Pacific Islander; Black or African American; Other, Unknown, or Missing; Multi-Racial; White
  4. Ethnicity - Hispanic or Latino; Not Hispanic nor Latino; Unknown or Missing
  5. Sex (Gender) - Female; Male
  6. Age Groups - age 0-4 years; and 5 year age groups through age 84; age 85 and older)
How? The Request screen has sections to guide you through the making a data request as step-by-step process. However, to get your first taste of how the system works, you might want to simply press any Send button, and execute the default data request. The data results for your query appear on the Table screen. After you get your data results, try the Chart and Map screens. Or export your data to a file (tab-delimited line listing) for download to your computer.

For more information, see the following:

Quick Start Guide;
Step 1, Organize your request;
Step 2, Select location and time;
Step 3, Select demographics;
Step 4, Other Options.

'By-Variables' Select variables that serve as keys (indexes) for organizing your data. See How do I organize my data? for more information.
Note:   To map your data, you must select at least one geographical location as a "By-Variable" for grouping your data, such as Region or State.
Help Click on any button labled "Help", located to the right hand side of the screen at the top of each section. Each Control's label, such as the "Location" label next to the Location entry box, is linked to the on-line help for that item.
Send Sends your data request to be processed on the CDC WONDER databases. The Send buttons are located on the bottom of the Request page, and also in the upper right corner of each section, for easy access.


Step 1. Organize table layout:
Select up to five variables that serve as keys for grouping your data. For example, you could select to group (summarize, stratify, index) your data by State, County, Race and Age.
How?    See How do I organize my data? for more information.

Hints:   

  1. To make a map, you must request data with a geographic location variable, such as Region or State, as a "By-Variable." Then click the Map tab.
  2. You cannot make charts when your data has more than two By-Variables.
  3. You cannot make charts for data grouped by State and also by County, because the number of states per each region varies.
Title  Enter any desired description to display as a title with your results.

Notes:   
  • The Race and Ethnicity categories available change over time:
    • 1970 - 1989
      The racial categories "American Indian or Alaskan Native" and "Asian or Pacific Islander" did not exist in Census data before 1990. Before 1990 these racial categories were included within the race category "Other, Unknown or Missing". Counts for other racial categories went down when the new categories came into existence.
      The Ethnicity categories indicating "Hispanic or Latino" identity did not exist in Census data before 1990. Before 1990 the Ethnicity category is coded as "Unknown or Missing". Caution should be exercised when making queries that include years both before and after 1990 and that display results by Race or by Ethnicity.
    • 1970 - 1999
      The "Multi-Racial" category, for persons describing their identity with two or more races, did not exist in Census data before 2000. Before 2000, persons were categorized to only one racial group, and thus the "Multi-Racial" category reports zero counts. Counts for other racial categories went down when the new category came into existence. Caution should be exercised when making queries that include years 2000 and before, that display results by Race.
  • Location boundaries change over time. See Changes in Geographic Areas for more information.

Step 2. Select location:

Limit the population to specific location here. Alternately, you can leave the settings at the default values (the United States) and choose to organize or group the data results by State or County to show these stratifications.

Location

This dataset includes national, state and county locations (no territories). Use this field to specify the location or locations for the query. Locations are specified by entering standard state (e.g. 01) FIPS codes, one per line. Any number of locations can be specified here.

How?  

Notes:   

  • About state and county codes:
    The unique state and county codes are Federal Information Standard Processing (FIPS) codes. Please see State FIPS Codes (tab-delimited text) and County FIPS Codes (spreadsheet) and for tables of the location names, FIPS codes and footnotes.
  • About location changes:
    County and Census Area boundaries change over time. Please see Location Changes for more information.

Step 3. Select years and demographics:
Limit your data for any of the following data elements:
  1. Year - 2003-2004.
  2. Age - age groups (age 0-4 years, 5 year age groups through age 84, age 85 and older)
  3. Sex (Gender) - Female; Male
  4. Race - American Indian or Alaska Native; Asian or Pacific Islander; Black or African American; Multi-Racial; Other, Unknown or Missing; White (Caucasian)
  5. Ethnicity - Hispanic or Latino; Not Hispanic nor Latino; Unknown or Missing

Year

Pick any combination of years desired.
How?   See How do I select items from the list box?.

Age Groups

The Age Groups field contains values beginning age 0-4 years, in 5-year groupings from 5 years through 84 years, and age 85 years and older. Select any combination of values.

How?   See How do I select items from the list box?.

Notes:
When the data results are exported to a file, the Age Group Code is shown, as well as the sort sequence value. The Age Group Code is PHIN compatible through age 84 years.

Age Group Code Sequence
"0-4 years" "0-4" 1
"5-9 years" "5-9" 2
"10-14 years" "10-14" 3
"15-19 years" "15-19" 4
"20-24 years" "20-24" 5
"25-29 years" "25-29" 6
"30-34 years" "30-34" 7
"35-39 years" "35-39" 8
"40-44 years" "40-44" 9
"45-49 years" "45-49" 10
"50-54 years" "50-54" 11
"55-59 years" "55-59" 12
"60-64 years" "60-64" 13
"65-69 years" "65-69" 14
"70-74 years" "70-74" 15
"75-79 years" "75-79" 16
"80-84 years" "80-84" 17
"85+ years" "85+" 18

Gender

Select Male, Female or All values.

How?   See How do I select items from the list box?.
Notes:   
WONDER codes for gender are PHIN standards compliant. The code for Female is "F" and the Male is "M".

Race

Select any combination of values: All races; American Indian or Alaska Native; Asian or Pacific Islander; Black or African American; Multi-Racial; Other, Unknown or Missing; White (Caucasian).

How?   See How do I select items from the list box?.
Notes:   
  • The Race categories available change over time:
    • 1970-1989:
      The racial categories "American Indian or Alaskan Native" and "Asian orPacific Islander" did not exist in Census data before 1990. Before 1990 these racial categories were included within the race category "Other, Unknown or Missing". Counts for other racial categories went down when the new categories came into existence.
    • 1970-1999
      The Multi-Racial category, for persons describing their identity with two or more races, did not exist in Census data before 2000. Before 2000, persons were categorized to only one racial group, and thus the "Multi-Racial" category reports zero counts. Counts for other racial categories went down when the new category came into existence. Caution should be exercised when making queries that include years 2000 and before, that display results by Race.
  • The Race field contains the race category as defined by PHIN coding standards. However, the "Asian or Pacific Islander" category does not match PHIN coding standards; all other WONDER race category codes are PHIN compliant.
Race Code Sequence
"American Indian or Alaska Native" "1002-5" 1
"Asian or Pacific Islander" "A-I" 2
"Black or African American" "2054-5" 3
"Other, Unknown, or Missing" "O" 4
"Multi-racial" "M-R" 5
"White" "2106-3" 6

Ethnicity

Select any combination of values: All Ethnicities, Hispanic or Latino, Not Hispanic nor Latino.

How?   See How do I select items from the list box?.
Note:    WONDER Hispanic origin codes are PHIN standards compliant.

NCHS Original
Code
WONDER Code
Description
1 2186-5 NOT HISPANIC nor LATINO
2 2135-2 HISPANIC or LATINO

Step 4. Other options:
Export Results   If checked, then query results are exported to a local file. More information on how to import this file into other applications can be found here.
How?   See CheckBox.
Show Totals   If checked, then totals and sub-totals display in the results table.
How?   See CheckBox.
Show Zero Values   If checked, then rows containing zero counts display in the results table. If unchecked, then zero count rows are suppressed.
How?   See CheckBox.
Precision   Precision is not available for this dataset because population counts are whole numbers.
Data Access Timeout   This value specifies the maximum time to wait for the data access for a query to complete. If the data access takes too long to complete, a message will be displayed and you can increase the timeout or simplify your request. If you can't complete a request using the maximum timeout, contact user support and we will try to run a custom data request for you.

Data Source Information

To learn more about the methods and source of these data please refer to:

1970-1979:
Intercensal County Estimates 1970-79
1980-1989:
Intercensal County Estimates 1980-1989
1990-2000:
Postcensal County Estimates 1990-1999
Postcensal State Estimates 1990-1999
Model
1990 Starting Population
Vital Statistics
Internal Migration
Inter-National Migration
Consistency with Previous Estimates
Limitations
References
Conversion of NCHS Categories

Additional Information

Suggested Citation United States Department of Commerce, U.S. Census Bureau, Population Division; Census Population 1970-2000 for Public Health Research, CDC WONDER On-line Database, March 2003.

Each original series of estimates has a unique citation. Please refer to Data Source Information for the original technical reference notes and citation for a specific series.

Notes:
  • Postcensal population estimates are estimates made for the years following a census, before the next census has been taken. Postcensal estimates are derived by updating the population enumerated in the decennial census using various measures of population change.
  • Intercensal population estimates are made for the period of time between decennial census years after the second census is completed, and such estimates replace the previous population projections for the time period. The 1990-1999 bridged-race intercensal estimates, which represent a revision of the annual time series of July 1 county postcensal population estimates by age, sex, race and Hispanic origin, were produced by the Population Estimates Program of the U.S. Bureau of the Census with support from the National Cancer Institute (NCI). These intercensal population estimates are based on the bridged single-race estimates of the April 1, 2000 resident population developed by the Bureau of the Census in collaboration with the National Center for Health Statistics (NCHS).
  • The potential for error is greatest for the smallest population groups, particularly the smaller race groups and county level estimates. Although efforts were made to use the best available data and methods to produce the estimates, the modeling process introduces error into the estimates.
  • See Changes in Geographic Areas for details of specific county-level changes that affect population counts.

Intercensal County Estimates 1970-1979

The data from 1970 -1979 is from the Intercensal Estimates of the Population of Counties by Age, Sex and Race: 1970-1980 (machine-readable data file) prepared by the Bureau of the Census, 1984. This data contains intercensal estimates of the resident population by age, sex, and race for each year July 1, 1971 to July 1, 1979. For methodology and other information, please see the scientific documentation file for the data at Intercensal Population Estimates, Bureau of the Census, 1970-1980

Intercensal County Estimates 1980-1989

Provisional Intercensal County
Age-Sex-Race Estimates
1980-1989

The data was produced by Demo-Detail, as a set of 3 estimates (White, Black, and Other) for each county, for each year 1980-1989. For the documentation provided with the original release of the 1980-1988 data, see Postcensal Population Estimates, Demo-Detail 1980-1988. The following discussion is an excerpt from the documentation for the original data:


Methodology 1980-1989

The Census Bureau estimates are produced by a cohort-component model which carries the 1980 census population counts forward by age, sex, and race using registered birth and deaths, and migration estimates derived from 1980 census data on gross out- and in-migration for the period 1975-80. Data on international immigration are introduced and special estimates are made of the military, college and institutional population in counties where these groups are important.

Demo-Detail's 1980-88 estimates are adjusted to agree with the Census Bureau's national estimates by age, sex, and race in Current Population Reports, Series P-25, No. 1022 , and with estimates of the total population of each county prepared by the Federal-State Cooperative Program for Population Estimates (FSCP), and published in Current Population Reports, Series P-26, Nos. 85 and 87.

The Census Bureau age-sex-race estimates for 1982, 1984, and 1985 were adjusted to agree with these race controls, and then readjusted to agree with national estimates by age, sex, and race, and with the FSCP estimates. These adjustments were made by first subtracting an estimate of the military, college, and institutional population from total, and adjusting the residual (an approximation of the "household" population) to achieve conformity with the control. Due primarily to sample variation, the Census Bureau's methodology produced unreasonable results for small minority race populations, and for this state, a special set of estimates, prepared by an alternative methodology developed in-house, was substituted for the set based on the Bureau's estimates.

The extensions to 1988 were developed with procedures which have been shown to produce reasonably accurate estimates when tested against actual census data. The basic extension is carried out for the "household" population, to which is added separate estimates for the special population groups. More information on the extensions and the alternate series mentioned above is available on request from Demo-Detail.

Demo-Detail did not plan to produce 1980-1990 intercensal county age estimates until final 1990 census data were available in com- plete detail. In January, final population totals for counties were released by the U.S. Bureau of the Census, but it now appears unlikely that the final age-sex-race data will be forthcoming until July, and perhaps not then. Accordingly, Demo-Detail developed an intercensal set of estimates using data at hand.

These provisional intercensal county estimates are essentially an extension and adjustment of the 1980-1989 postcensal estimates that were previously released. The estimates are in the usual detail, with 18 five-year age groups (0-4, 5-9, 10-14, etc. to 85+) for White, Black, and Other, by sex, for every year, 1980 to 1990.

The first step was to extend the 1989 estimates to 1990 in all detail, at the same time making minor revisions to the 1986-1989 estimates using improved methodology. The total population of each county on April 1, 1990 was then obtained by interpolation between the July 1, 1989 and 1990 estimates. The average deviation of these county totals from the 1990 census counts was just under 4 percent, a figure very close to that obtained by the Census Bureau in its formal evaluation of their county estimates for the decade 1970-1980. There were, however, a number of large deviations. The twenty highest and lowest ratios of the estimates to the census counts are shown in Appendix A (in the original publication).

The 1990 age-sex-race estimates for each county were adjusted pro rata to agree with the census total (brought forward to July 1). In making all adjustments, Demo-Detail first obtained an approximate household population by subtracting out the special populations (military, college, and prison), and adjusting only this "household" population. This precaution has an important impact if the special population is a substantial proportion of the total population, and if the adjustment is large. Fredericksburg, VA, which leads the list in Appendix A (in the original publication) is a case in point, having a relatively large college population, predominately female.

The estimates for the intermediate years 1981 to 1989 were adjusted to allow for the 1990 percent deviation using a simple straight- line procedure. The 1981 estimates were adjusted by one-tenth of the 1990 deviation, the 1982 estimates by two-tenths, and so on.

As always, the estimates which emerged from these adjustments were controlled to national totals. For this purpose, a special set of intercensal national estimates was constructed. The Census Bureau published an estimate of 247,466,000 for the resident population on July 1, 1990, based on the 1990 census count. This is about 0.4 percent below the total Demo-Detail had obtained by bringing forward the Bureau's national estimates as published in Current Population Reports, Series P-25, No. 1057, using change in the national pro- jections for fiscal year 1990 (Series P-25, No. 1018). Our 1990 age-sex-race detail for the nation was adjusted pro rata to agree with the new total. The detail for the intermediate years 1981 to 1989 was obtained by adjusting the Census Bureau's published estimates of the resident population, using the straight line procedure described above for individual counties.

The intercensal county age-sex-race estimates obtained by the procedures described above provide a significantly improved data set for use until a definintive set based on complete 1990 census detail can be developed.

Source: Postcensal Population Estimates 1980-1988, Demo-Detail

Postcensal County Estimates 1990-1999

Estimates of the Population of Counties
by Age, Sex and Race/Hispanic Origin:
1990 to 1999

The 1990-1999 data was produced by the Bureau of Census for use by the Centers of Disease Control in the calculation of vital rates. For the documentation provided with the original release of the 1990-1994 data, see Postcensal Population Estimates, County Level 1990-1994 . For the record layout of the original 1990-1999 data set, see Postcensal Population Estimates, Race/Ethnicity, 1990-1999. The following is an excerpt from the original documentation:


Methodology 1990-1999

These data are estimates of the resident population of the 3,143 counties in the United States as defined in 1994, by 5-year age groups (ages 0 to 4, 5 to 9,...80 to 84, 85 and over), sex (male, female), and modified race/Hispanic origin (White non-Hispanic; White Hispanic; Black; American Indian, Eskimo and Aleut; Asian and Pacific Islander; and Total Hispanic) for July 1, 1990 through 1999. These estimates are consistent with: 1) the estimates of the population of States by age, sex, race, and Hispanic origin: July 1, 1990 to 1999 and 2) the 1991 through 1999 postcensal estimates of the total population of counties (available under separate cover as Series PE-21).

The county estimates included in this release are developed in a two-step procedure. First a set of state estimates by single years of age (Ages O, 1, 2,...85 and over), sex (male, female), modified race (White; Black; American Indian, Eskimo, and Aleut; Asian and Pacific Islander), and Hispanic Origin (Hispanic Origin, non- Hispanic Origin) are developed. These state estimates are developed using a cohort-component technique. A complete description of that methodology is included below (Appendix A in the original publication).

The estimates of the population of counties by age, sex, and race/hispanic origin are developed in a second step using a ratio method. The ratio method is a technique for adjusting data to sum to a pre-determined total. It consists of multiplying each element of the data by the ratio formed by dividing the desired total by the sum of the data. When there are multiple totals to which we wish to adjust our data, as with the county estimates, the Census Bureau first partitions the data into groups which correspond to the desired totals, then construct and apply ratios for each group using the same method as in the single-total situation. Applying the ratio method to a data set is referred to as raking.

The detailed state estimates by age, sex, race, and Hispanic Origin developed in step 1 are aggregated by state to five year age groups, sex, and race/hispanic categories. These aggregated state estimates along with the estimates of the total population of counties serve as the control totals for the estimates of the population of counties by age, sex and race/hispanic origin. The methodology used to develop the estimates of the total population of counties is described in "Subnational Estimates of Total Population by the Tax Return Methodology" by Michael Batutis (available from the Population Division, US Bureau of the Census).

The April 1, 1990 modified census counts for counties by age, sex, and modified race/hispanic origin released as computer tape file MARS, STF-S-3 are used as the starting point. For July 1, 1990, the census level county-level MARS data were raked to:

1) the estimates of State population by five-year age group, sex, race and Hispanic origin developed in step 1; and
2) the 1990 estimates of the total population of counties.

The process was repeated for the 1991 through 1994 estimates adjusting the data cells to the appropriate set of state and county estimates.

It is important to note that our regularly published county and State estimates have been updated since the productions of these estimates. Consequently, there will be a slight discrepancy between these estimates and the most recently released county population estimates and State estimates by age and sex, since these estimates were controlled to an earlier version of the county and State estimates.

These data were developed as part of an ongoing project to develop postcensal population estimates of states and counties by age, sex, race, and Hispanic origin. Though the method employed produced estimates which were fully disaggregated with respect to race and Hispanic origin, the limitations of this approach are such that we felt it necessary to combine the fully disaggregated race-Hispanic origin categories into the categories used here. Work is continuing on methods and data sets that can be use'd to more directly estimate the age, sex, race, and Hispanic origin distributions of the State and county populations. As additional steps are completed, new estimates for subsequent years are preprared and the existing series is revised for previous years (back to 1990).

This data set contains population estimates disaggregated by five- year age groups, sex and race/Hispanic origin for each county. However the limitations of our methodology are such that these data are not considered accurate for each individual cell. Although measures of error are not available, it is recommended that aggregating the individual cells to larger groups will reduce the level of error. Although the data are unrounded, these data are not considered accurate to the last digit.

Postcensal State Estimates 1990-1999

The state estimates are consistent with the postcensal estimates for the Nation and States by age, sex, race and Hispanic origin for 1990 through 1999 published in Current Population Reports, Series P-25, No. 1127

Model 1990-1999

The State estimates included in this release are developed using a cohort-component method whereby each component of population change -- births, deaths, domestic migration, and international migration is estimated separately for each birth cohort by sex and race.

The cohort-component method is based on the traditional demographic accounting system:

P1 = P O + B - D + NDM + NMA
where:
P1 = population at the end of the period
PO = population at the beginning of the period
B = births during the period
D = deaths during the period
NDM = net domestic migration during the period
NMA = net migration from abroad during the period
To generate population estimates with this model, the census Bureau first developed separate data sets for each of these components. The procedures by which these data are developed by single year of age, sex, race, and Hispanic origin are described in the following sections. Once the data for each component were developed, the estimates could be produced simply by adding the components together, with the exception of internal migration. The reason for this exception and our procedure for dealing with internal migration are explained in the internal migration section below.

This overall approach is similar to that used in the development of the experimental set of state and metropolitan area estimates by race and, Hispanic origin. The Current Population Reports, Series P-25, No. 1040-RD-I , provides a detailed discussion of this general approach.

1990 Starting Population

The April 1, 1990 Census data files which were used as the starting points in this methodology represent the Modified Age, Race, Sex, and Hispanic origin (MARS) census data released as computer tape file (MARS, STF-S-3). The modification methodology is outlined in Census Report, CPH-L-74.

In order to develop the desired July 1, 1990 starting point from the April 1, 1990 data, the census Bureau used the ratio method to make the April 1 data consistent with the July 1, 1990 national population estimates by age, race, sex, and Hispanic origin and consistent with the July 1, 1990 state population estimates by age and sex. The ratio method is a technique for adjusting data to sum to a pre- determined total, which consists of multiplying each element of the data by the ratio formed by dividing the desired total by the sum of the data. When there are multiple totals to which the census Bureau wishes to adjust our data, as with the state age-sex estimates, first the data is partitioned into groups which correspond to the desired totals, then construct and apply ratios for each group using the same method as in the single-total situation. Applying the ratio method to a data set is referred to as "raking."

Vital Statistics 1990-1999

The data for births and deaths used in these estimates are based on 1) detailed data available from the National Center for Health Statistics (NCHS); 2) estimates of births and deaths for counties developed by the member agencies of the Federal State Cooperative Program for Population Estimates (FSCPE); and 3) estimates of births and deaths by detailed demographic characteristics developed as part of the Population Division program for national population estimates.

Births-- Extracts of detailed individual-record data on births from NCHS for calendar years 1990 through 1993 are used to construct the state-level births. The race and Hispanic origin codes on the individual NCHS records were converted into our four race and two-Hispanic origin system as shown on the attached chart. The individual records for events occurring July 1, 1991 through June 30, 1993 are aggregated by year to the county level and adjusted to the county-level data provided by the FSCPE member agencies. These results are further adjusted to agree with national-level race-Hispanic origin estimates developed as part of the national population estimates program (see reference 4, page 5).

To estimate the July 1, 1993 through June 30, 1994 period, first the individual records for events occurring for the six month period July 1, 1993 through December 31, 1993 are aggregated. Because the 1994 data were not available when the original set of estimates was developed, an alternative method was used to estimate the detailed data for the January 1 to June 30, 1994 period. To do this, the six month aggregations for July through December were adjusted to:

  1. preliminary estimates of births for July 1993 through June 1994 provided by the FSCPE agencies; and
  2. to preliminary estimates of national level births by race, sex and Hispanic origin for the July 1993 through June 1994 period, developed as part of the national estimates program (see reference 4, page 5).

Deaths -- The estimates of deaths are developed in the same manner as that for births. However, because death data have the additional dimension of age, the resultant number of national controls was too great to be handled simultaneously with the county-level controls. Consequently, state-level death estimates were prepared independently of the county- level estimates, by summing individual records to the state level by age, race, Hispanic origin, sex, and period, and adjusting these totals to national-level age-race-Hispanic origin controls.

To develop the deaths by age, the age at death and the date of birth information on the individual record was examined. If the date of birth information was missing, age was set to the most recent valid value. The preliminary age at death value was computed using date of birth information. This preliminary value was compared to the age at death value on the individual record. If the difference between these two values was no greater than two years, the computed value was used. If not, the age at death value on the certificate was used.

Internal Migration 1990-1999

The values for internal migration used in these estimates are developed using a variant of the basic administrative records method. The development of the data rely upon two basic files - an annual extract of tax returns provided by the Internal Revenue Service (IRS), and a 20% sample of information on the Social Security Administration Application File (NUMIDENT) which includes Social Security Number (SSN), month and year of birth, race, sex, and 6 characters of the last name.

The basic Administrative Records method relies upon annual extracts of tax returns provided by the IRS. In this approach, using the SSN on the return, the tax returns for two years are matched to obtain state of residence for the two periods. By comparing the state of residence at the two points in time, annual measures of migration for states are developed.

Because the standard tax return provides no demographic characteristics of the tax filer, the basic administrative record method provides data for the total population only. To extend this approach to demographic characteristics, the Census Bureau relies upon an extract of the NUMIDENT file. Because the Census Bureau is able to receive only a 20-percent sample of this basic NUMIDENT file, the Census Bureau only appends the demographic characteristics of the primary filer to the same 20-percent sample of tax returns.

In addition to demographic characteristics of the primary filers, the model required demographic characteristics of those persons claimed as exemptions on the tax return. The rules for assigning demographic characteristics to dependents are straight forward and rely on basic familial and demographic relationships.

  1. Spouses on the tax return are given the age and race/Hispanic origin of the primary filer. They are assigned the opposite sex of the primary filer.
  2. Dependent children are given the race/Hispanic origin of the primary filer and all assigned to the age group under 20. Sex was not assigned to the dependent children category.
  3. Parent exemptions are assigned the race/Hispanic origin of the primary filer and all assigned to the age group 65 and over.
  4. Other dependents are assigned the race/Hispanic origin of the primary filer and all assigned the age group under 20.
In order to develop an estimate for July 1 of a given year using the cohort-component method, an estimate of the migration which took peace between July 1 of the preceding year and June 30 of the year in question is needed. However, the migration data obtained using the administrative records method pertain to time periods determined by when the individual tax-payers file their returns, which, of course, varies from tax-payer to tax-payer. Since most tax returns are filed between January and April, it is roughly correct to say, for example, that the migration data obtained as a result of matching returns from tax years 1989 and 1990 pertains to a (one-year) period within the interval from January 1990 (the earliest most tax-payers would file their 1989 returns) to April 1991 (the latest most tax-payers would file their 1990 returns). it is assumed that this is a reasonable approximation to the interval needed for our 1991 estimates and, similarly, that the data from the tax years 1990-1991, 1991-1992, and 1992-1993 match are appropriate for our 1992, 1993, and 1994 estimates, respectively. These assumptions are based on our research which indicates that state-to-state migration rates change on average only about 15% a year, and these changes tend to offset one another when out-rates and in-proportions are calculated.

The migration data yielded by the method described above consists of counts of those tax-filers whose SSNs were in the 20% sample plus the dependents claimed by those filers, disaggregated by state of origin, state of destination, age, race, sex, and, Hispanic origin. The first step in converting these counts into the statistics actually used in our estimates is to construct state-to- state migration rates by demographic characteristic (i.e. age, race, sex, and, Hispanic origin). This is done by summing all the counts for a given origin by characteristic and then dividing each count by the sum for that characteristic.

Because of the potentially large number of origin-destination- characteristic combinations, it is necessary to collapse age into categories to avoid stretching the data too thin. The categories selected are 0-19, five-year categories from 20-24 to 60-64, and 65 and over. The 0-19 and 65+ categories were selected because we have no age information for dependents, and all dependent children are assigned to the 0-19 category and all dependent parents of filers to the 65+ category. Once the state-to-state rates are used to derive out-rates and in-proportions using the method described below, the out-rates and in-proportions are converted from age- groups to single years by giving each year the value of the group to which it belongs except for those years which form age-group boundaries (e.g. 19 and 20), which are averaged. This is done to prevent drastic changes between years.

An additional problem is created by the fact that the SSA data have only three race categories: White, Black, and Other. In order to convert from this system into the four race system used in these estimates, it is necessary to split the "Other" category into American Indian, Eskimo and Aleut (AIEA) and Asian & Pacific Islander (API). This split is based on the relative sizes of the total, AIEA and API populations in the origin state for the out- rates and on the relative sizes in the destination state for the in-proportions. The racial composition of migration flows depends upon the racial composition of both the origin and the destination, so that in reality this "Other" group probably has a different composition for each of the 2550 different state-to-state flows, but the numbers involved are too small to permit separate analysis for each flow. By combining the state-to-state rates into out-rates and in-proportions, with the method described below, we greatly increase the number of observations underlying each of our statistics and have the ability to base our rate calculations solely on origin characteristics and our proportions solely on destination characteristics. These separate rates and proportions for the four race groups were applied only to the non-Hispanic population. One set (by age and sex) of migration rates and proportions are computed for Hispanics without regard to race and applied to all Hispanic race groups.

The creation of out-rates and in-proportions from the state-to- state migration rates involves converting the origin-destination- characteristic-specific rates into origin-characteristic-specific rates and destination-characteristic-specific proportions. In this process, all calculations are performed separately for each combination of demographic characteristics. The state-to-state migration rates are multiplied by our starting population estimate for the appropriate group to obtain an estimate of the total migration flow between the states in question for this group. These flows are summed to get total out- and total in-migration by characteristic for each state. Each state's out-migration totals are divided by their respective populations to obtain out-migration rates and the out-migration totals are summed across states to obtain the national total of migration by demographic characteristic. These national totals are divided into each state's in-migration totals to obtain the in-migration proportions. It should be noted that the population figures used in these calculations are our starting population estimates, since at this stage of the process there are no population estimates for the periods to which the migration rates pertain (except for the 1991 estimates, for which our starting population is the beginning-of- period population). The out-rates and in-proportions are converted into actual estimates of migration within the process which produces the finished population estimates, since it is only at this point that the population figures needed are available. This conversion is accomplished by multiplying each state's out-rates by the respective beginning-of-period population to obtain our estimate of that state's out-migration, which is then summed across states to obtain national-level migration. Finally, each state's in-proportions are multiplied by the national-level migration to get that state's in-migration estimates.

Inter-National Migration 1990-1999

The international migration component in these estimates is an aggregation of four separate parts: 1) alien immigration, refugees, and net undocumented migration; 2) legal emigrants; 3) net movement between Puerto Rico and the mainland; and 4) net movement of federal civilian citizens.

Immigration (including refugees and undocumented). Based on Legal immigration data developed from the Immigration and Naturalization Service public use microdata, refugee data drawn from unpublished reports of the Office of Refugee Resettlement, and net undocumented immigration files developed as part of the national estimates program (see reference 5, pages 24-29). The legal immigration and refugee files both possess full demographic detail and state-level geography for both years in question. The file on net undocumented immigration contains full demographic detail at the national level, but no state-level information. The Census Bureau gave undocumented immigration the state-level distribution of the emigrants by raking the emigrant file to the undocumented's national distribution.

Legal emigration. The Census Bureau began with state-level data on legal emigration with race and ethnic detail (see reference 6), to which the Census Bureau applied the age-sex distribution from the emigration data used in our state projections (see reference 2, page xxvii). The resulting data were raked to national- level controls developed for the national estimates program (see reference 5, page 38). Emigration was assumed to remain constant over the estimation period.

Net Puerto Rican migration. The Census Bureau utilized a national-level file on net Puerto Rican migration with full demographic detail for both years developed as part of the national estimates program (see reference 3, page 6). This net migration was distributed to the states based on their respective portions of the Puerto Rican migration developed from past research (see reference 6).

Net federal citizen migration. The Census Bureau utilized a national-level file on net federal citizen migration with full demographic detail for both years developed as part of the national estimates program (see reference 3, pages 6-7). State-level distributions were obtained using the IRS-SSA data employed in the internal migration estimates, which also contains data on movements to and from foreign countries. The Other races distribution was used for both, AIEA and API, and the below 20 and above 65 age distributions were taken from the national distribution. These state-level distributions were raked to the national-level distribution to yield the final data.

Consistency with Previous Estimates 1990-1999

Once the cohort-component method described above is used to produce preliminary population estimates, then the ratio method is used to make these estimates consistent with previously published State and National estimates (for a description of past State estimates, see reference 1 below). This is done by raking each year of the new estimates to the corresponding year's National estimates by age, sex, race, and, Hispanic origin and to the corresponding year's State estimates by State, age, and sex. Because this procedure produces fractional numbers, a special rounding routine is applied which transforms all individual estimates into integers while preserving their consistency with the State and National controls.

It is important to note that our regularly published State and national estimates have been updated since the production of these estimates. Consequently, there is a slight discrepancy between these estimates and the most recently released national estimates and State estimates by age and sex, since these estimates were controlled to an earlier version of the State and national estimates.

Limitations for 1990-1999 Postcensal Estimates

These data were developed as part of an ongoing project to develop postcensal population estimates of states and counties by age, sex, race, and, Hispanic origin. These estimates represent an intermediate step in this overall project. Work is continuing on methods and data sets that can be used to more directly estimate the age, sex, race, and Hispanic origin distributions of the state and county populations. As additional steps are completed, the planning for subsequent years is updated and the post censal estimates for previous years are revised.

The postcensal 1990-1999 data set contains population estimates disaggregated by single year of age, sex, race, and, Hispanic origin for each state. However, the limitations of the methodology are such that these data are not considered accurate for each individual cell. Although measures of error are not available, it is suggested that aggregating the individual cells to larger groups will reduce the level of error. The data is unrounded, and is not considered accurate to the last digit.

References for the 1990-1999 Postcensal Estimates
  1. Batutis, Michael J., "Subnational Estimates of Total Population by the Tax Return Methodology", Population Division, U.S. Bureau of the Census, Washington, DC, 1994.
  2. Campbell, Paul R., Population Projections for States, by Age, Race, and Sex: 1993 to 2020, U.S. Bureau of the Census, Current Population Reports, P25-1111, U.S. Government Printing Office, Washington, DC, 1994.
  3. Deardorff, Kevin E., Frederick W. Hollmann, and Patricia Montgomery, "U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1990 to 1994", U.S. Bureau of the Census, PPL-21, 1995.
  4. Hollmann, Frederick W. United States Population Estimates, by Age, Sex, Race, and Hispanic Origin: 1980 to 1988, U.S. Bureau of the Census, Current Population Reports, Series P-25, No.1045, U.S. Government Printing Office, Washington, DC, 1990.
  5. ______________. "U.S. Population Estimates, by Age, Sex, Race, and Origin: 1990 to 1993", U.S. Bureau of the Census, PPL-8, 1994.
  6. Word, David L. "The Census Bureau Approach for Allocating Internal Migration to States, Counties and Places:1981- 1991", U.S. Bureau of the Census, Technical Working Paper No. 1, 1992.

Conversion of National Center for Health Statistics (NCHS)
Race, Ethnicity, and Age for State Estimates 

                                                      RACE
NCHS                                                        State Estimates

(1) White ------------------------------------------------  White
(2) Black  -----------------------------------------------  Black
(3) American Indian, Eskimo or Aleut ---------------------  American Indian,
					                    Eskimo, or Aleut
(4) Chinese ---------------------------------------|
(5) Japanese --------------------------------------|
(6) Hawaiian  -------------------------------------|______  Asian and Pacific
(7) Filipino  -------------------------------------|        Islander
(8) Other API -------------------------------------|
(9) Other Race ------------------------------------|

                                                      ETHNICITY
NCHS                                                        State Estimates

(00) Non-Hispanic ----------------------------------------  Non-Hispanic
(01) Mexican --------------------------------------|
(02) Puerto Rican ---------------------------------|
(03) Cuban ----------------------------------------|______  Hispanic
(04) Central of South American --------------------|
(05) Other Hispanic -------------------------------|
(99) Unknown, not asked ----------------------------------  Allocated
                                                            according to
                                                            proportion
                                                            Hispanic for
                                                            appropriate
                                                            sub-group in
                                                            MARS file.

Source: Postcensal Population Estimates 1990-1999, US Census Bureau

Changes in Geographic Areas

  • 1970-1979:   The following changes to counties occurred after the 1970 Census and are reflected in later population estimates:
    1. In 1975 Anchorage City, Alaska and Greater Anchorage Area Borough, Alaska were combined to form Anchorage, Alaska (FIPS code 02020). This change was made retroactive in the Census data begining in 1970.
    2. In 1979 in order to achieve alphabetical consistency, the FIPS code for Ste. Genevieve, Missouri was changed from 29193 to 29186. This change was made retroactive in the Census data begining in 1970.
    3. Petersburg City, Virginia (FIPS code 51730) annexed part of Dinwiddie County, Virginia (FIPS code 51053) and part of Prince George County, Virginia (FIPS code 51149) effective December 31, 1971. This change was made in the data begining in 1972.
    4. Bristol City, Virginia (FIPS code 51520) annexed part of Washington County (FIPS code 51191). This change was made in the Census data begining in 1974.
    5. Roanoke City, Virginia (FIPS code 51770), annexed part of Roanoke County, Virginia (FIPS code 51161) effective December 31, 1975. This change was made in the Census data begining in 1975.
    6. Lynchburg City, Virginia (FIPS code 51680)annexed part of Bedford County (FIPS code 51019) and part of Campbell County (FIPS code 51031) effective date December 31, 1975. This change was made in the Census data begining in 1975.
    7. In 1975 Poquoson City, Virginia (FIPS code 51735) was split from from York County, Virginia (FIPS code 51199). This change was not made in the Census data until 1980.
    8. In 1975 Manassas Park City, Virginia (FIPS code 51685) was split from Prince William County, Virginia (FIPS code 51153). This change was not made in the Census data until 1980.
    9. In 1975 Manassas City, Virginia (FIPS code 51683) was split from Prince William County, Virginia (FIPS code 51153). This change was not made in the Census data until 1980.
    10. North Slope Borough, Alaska (FIPS code 02185) was created in the 1970's from Barrow Division, Alaska (FIPS code 02040). This change was not made in the Census data until 1980.
    11. Skagway-Yakutat-Angoon Census Area, Alaska (FIPS code 02231) was created in the 1970's by combining Angoon Division, Alaska (FIPS code 02030) and Skagway-Yakutat Division, Alaska (FIPS code 02230). This change was not made in the Census data until 1980.
    12. The Valdez-Cordova Census Area, Alaska (FIPS code 02261) was created in the 1970's by combining Cordova-McCarthy Division, Alaska (FIPS code 02080), part of Southeast Fairbanks Division, Alaska (FIPS code 02240), Valdez-Chitina-Whittier Division, Alaska (FIPS code 02260). This change was not made in the Census data until 1980.
    13. Kenai Peninsula Borough, Alaska (FIPS code 02122) was created in the 1970's by combining Kenai-Cook Inlet Division, Alaska (FIPS code 02120) and Seward Division, Alaska (FIPS code 02210). This change was not made in the Census data until 1980.
    14. In the 1970's part of Kuskokwim Division, Alaska (FIPS code 02160) was added to Bethel Census Area, Alaska (FIPS code 02050). This change was not made in the Census data until 1980.
    15. Kuskokwim Division, Alaska (FIPS code 02160) was eliminated in the 1970's. Parts of Kuskokwim were added to Bethel Census Area, Alaska (FIPS code 02050) and Yukon-Koyukuk Census Area, Alaska (FIPS code 02290). This change was not made in the Census data until 1980.
    16. Prince of Wales-Outer Ketchikan Census Area, Alaska (02201) was created in the 1970's by combining Prince of Wales Division, Alaska (FIPS code 02200) and Outer Ketchikan Division, Alaska (FIPS code 02190). This change was not made in the Census data until 1980.
    17. Southeast Fairbanks Census Area, Alaska (FIPS code 02240) in the 1970's increased in size by receiving part of Upper Yukon Division, Alaska (FIPS code 02250). This change was not made in the Census data until 1980.
    18. Upper Yukon Division, Alaska (FIPS code 02250) was eliminated in the 1970's. Parts of Upper Yukon were added to Southeast Fairbanks Census Area, Alaska (FIPS code 02240) and Yukon-Koyukuk Census Area, Alaska (FIPS code 02290). This change was not made in the data until 1980.
    19. Yukon-Koyukuk Census Area, Alaska (FIPS code 02290) in the 1970's increased in size by receiving part of Upper Yukon Division, Alaska (FIPS code 02250) and part of Kuskokwim Division, Alaska (FIPS code 02160). This change was not made in the Census data until 1980.
  • 1980-1989:   The following changes to counties occurred with the 1980 Census and are reflected in Census 1980 and later population estimates:
    1. Beginning in 1980, Washbaugh County, South Dakota (FIPS code 46131) is combined with Jackson County, South Dakota (FIPS code 46071)."
    2. Beginning in 1980, Nansemond City, Virginia (FIPS code 51123), an independent city, was integrated into Suffolk City, Virginia (FIPS code 51800)."
    3. Fairfax City, Virginia (FIPS code 51600) annexed part of Fairfax County (FIPS code 51059) effective December 31, 1980. This change was made in the Census data begining in 1980.
    4. In 1981 Cibola County, New Mexico (FIPS code 35006) was formed when Valencia County, New Mexico (FIPS code 35061) was divided into two parts. This change was made retroactive in the Census data begining in 1980.
    5. Harrisonburg City, Virginia (FIPS code 51660) annexed part of Rockingham County (FIPS code 51165) effective December 31, 1982. This change was made retroactive in the Census data begining in 1980.
    6. Fredericksburg City, Virginia (FIPS code 51630) annexed part of Spotsylvania County (FIPS code 51177) effective December 31, 1983. This change was made retroactive in the Census data begining in 1980.
    7. In 1983 La Paz County, Arizona (FIPS code 04012) was formed from the northern portion of Yuma County, Arizona (FIPS code 04027). This change was made retroactive in the Census data begining in 1980.
    8. Williamsburg City, Virginia (FIPS code 51830) annexed part of James City County (FIPS code 51095) effective December 31, 1983. This change was made in the Census data begining in 1984.
    9. Waynesboro City, Virginia (FIPS code 51820) annexed part of Augusta County (FIPS code 51015) effective December 31, 1985. This change was made retroactive in the Census data begining in 1980.
    10. Staunton City, Virginia (FIPS code 51790) annexed part of Augusta County (FIPS code 51015) effective December 31, 1986. This change was made retroactive in the Census data begining in 1980.
    11. In 1986 Kobuk Census Area, Alaska (FIPS code 02140) merged with part of North Slope Borough, Alaska (FIPS code 02185) to form Northwest Arctic Borough, Alaska (FIPS code 02188). This change was made retroactive in the Census data begining in 1980.
    12. In 1987 Aleutian Islands Census Area, Alaska (FIPS code 02010) was split into Aleutians East Borough, Alaska (FIPS code 02013) and Aleutians West Census Area, Alaska (FIPS code 02016). This change was made retroactive in the Census data begining in 1980.
    13. Danville City, Virginia (FIPS code 51590) annexed part of Pittsylvania County (FIPS code 51143) effective December 31, 1987 and December 31, 1988. This change was made retroactive in the Census data begining in 1980.
    14. Emporia City, Virginia (FIPS code 51595) annexed part of Greensville County (FIPS code 51081) effective January 1, 1988. This change was made retroactive in the Census data begining in 1980.
    15. In 1989 part of Dillingham Census Area, Alaska (FIPS code 02070) became Lake and Peninsula Borough, Alaska (FIPS code 02164). This change was made retroactive in the Census data begining in 1980.
  • 1990-1999:   The following changes to counties occurred after the 1990 Census and are reflected later population estimates:
    1. In 1999, Dade County, FL (FIPS code 12025) was renamed Miami-Dade County (new FIPS code 12086). The change is reflected in the data beginning in 1999.
    2. Beginning in 1999, Yellowstone National Park County, Montana (FIPS code 30113) was incorporated into Gallatin County, Montana (FIPS code 30031) and Park County, Montana (FIPS code 30067).
    3. In 1990 Denali Borough, Alaska (FIPS code 02068) was organized, mostly from the Yukon-Koyukuk Census Area, Alaska (FIPS code 02290) with a small part from Southeast Fairbanks, Alaska (FIPS code 02240).
    4. In 1999, South Boston, VA (FIPS code 51780), an independent city, was integrated into Halifax County, VA (FIPS code 51083) and is no longer a county equivalent. This change was made retroactive in the Census data beginning in 1990.
    5. Yakutat Borough, Alaska (FIPS code 02282), was established September 22, 1992. The new borough removes territory from Skagway-Yakutat-Angoon CA (FIPS code 02231). With the loss of Yakutat, that census area is renamed Skagway-Hoonah-Angoon Census Area (FIPS code 02232). This change was made in the Census data retroactive to 1990.
    6. Skagway-Yakutat-Angoon Census Area, Alaska (FIPS code 02231) was dissolved September 22, 1992. The former territory formed 2 new areas: Skagway-Hoonah-Angoon Census Area (FIPS code 02232) and Yakutat Borough, Alaska (FIPS code 02282). This change was made in the data retroactive to 1990.
    7. Skagway-Hoonah-Angoon Census Area, Alaska (FIPS code 02232) was established in 1992 from area formerly in Skagway-Yakutat-Angoon (FIPS code 02231). This change was made in the data retroactive to 1990.


This page last reviewed: Wednesday, August 29, 2007
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