Appendix B: Selected Standard Error Tables - Initiation of Marijuana Use: Trends, Patterns, and Implications Report

Appendix B: Selected Standard Error Tables

Table 3.1S Standard Errors of Estimated Numbers (in Thousands) of Persons Who First Used Marijuana During the Years 1965 to 1999, Their Mean Age at First Use, and the Annual Incidence Rates of First Use (Per 1,000 Person-Years of Exposure), for All Ages

Year Number of Initiates (1,000s) Mean Age at First Use Incidence Rates¹

1965 75 1.2 0.5

1966 114 0.5 0.8

1967 119 0.4 0.8

1968 136 0.4 0.9

1969 147 0.3 1.0

1970 164 0.3 1.1

1971 158 0.3 1.0

1972 157 0.3 1.0

1973 154 0.4 1.0

1974 150 0.3 1.0

1975 150 0.4 1.0

1976 163 0.3 1.1

1977 157 0.3 1.0

1978 162 0.3 1.0

1979 144 0.3 1.0

1980 127 0.5 0.8

1981 97 0.3 0.6

1982 101 0.5 0.6

1983 101 0.6 0.6

1984 95 0.4 0.6

1985 85 0.4 0.5

1986 74 0.3 0.4

1987 71 0.3 0.4

1988 73 0.2 0.4

1989 67 0.4 0.4

1990 59 0.6 0.4

1991 62 0.5 0.4

1992 54 0.2 0.3

1993 58 0.3 0.4

1994 63 0.2 0.4

1995 56 0.1 0.4

1996 66 0.3 0.4

1997 59 0.3 0.4

1998 61 0.4 0.4

1999² 61 0.2 0.4

¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years.
² Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.2S Standard Errors of Estimated Age-Gender Numbers (in Thousands) of Persons Who First Used Marijuana During the Years 1965 to 1999

Year Number of Initiates (1,000s)

Males 12-14 Females 12-14 Males 15-17 Females 15-17 Males 18-20 Females 18-20 Males 21+ Females 21+

1965 19 * 42 17 19 30 21 33

1966 22 * 42 32 66 44 42 39

1967 32 26 40 28 54 41 60 34

1968 27 16 47 26 83 47 69 51

1969 26 25 63 41 75 53 50 64

1970 38 43 64 51 67 46 62 51

1971 52 41 53 42 66 44 60 71

1972 48 31 82 61 56 40 57 59

1973 47 37 65 48 56 44 63 63

1974 40 45 68 56 45 49 50 56

1975 43 51 55 59 58 42 45 63

1976 38 34 84 69 62 45 53 63

1977 45 38 69 67 56 52 49 52

1978 41 40 79 68 42 54 45 55

1979 42 29 66 67 62 45 34 46

1980 24 20 61 54 36 50 47 49

1981 24 18 44 39 38 39 29 37

1982 24 19 37 37 41 38 46 47

1983 25 19 37 29 32 28 59 28

1984 29 21 34 31 32 26 39 40

1985 24 21 34 30 28 26 39 28

1986 19 17 33 33 26 22 30 25

1987 11 14 32 33 27 22 20 29

1988 14 9 36 31 24 19 31 33

1989 12 10 33 25 23 23 27 22

1990 12 10 28 19 24 18 21 30

1991 16 10 20 19 25 21 39 17

1992 14 14 21 17 23 19 19 17

1993 16 17 19 22 21 19 20 22

1994 18 19 24 22 17 22 25 17

1995 19 16 24 20 16 17 19 17

1996 17 16 26 25 17 17 18 28

1997 16 15 24 23 19 16 21 19

1998 17 14 23 20 17 18 31 19

1999¹ 20 18 28 24 17 19 22 27

* Low precision; no estimate reported.
¹ Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.3S Standard Errors of Estimated Numbers (in Thousands) of Persons Who First Used Marijuana During the Years 1965 to 1999, Their Mean Age at First Use, and the Annual Incidence Rates of First Use (Per 1,000 Person-Years of Exposure), by Gender

Number of Initiates (1,000s) Mean Age at First Use Incidence Rates¹

Year Males Females Males Females Males Females

1965 55 50 0.8 2.4 0.9 0.7

1966 92 70 0.5 0.9 1.4 0.9

1967 97 67 0.4 1.0 1.5 0.9

1968 122 76 0.4 1.0 1.8 1.0

1969 110 101 0.4 0.5 1.6 1.3

1970 123 94 0.4 0.5 1.8 1.2

1971 124 102 0.4 0.5 1.8 1.3

1972 126 101 0.5 0.4 1.8 1.3

1973 115 105 0.5 0.5 1.7 1.3

1974 106 105 0.4 0.4 1.6 1.3

1975 105 107 0.5 0.5 1.6 1.3

1976 122 111 0.3 0.4 1.7 1.4

1977 110 107 0.4 0.4 1.6 1.3

1978 107 114 0.4 0.5 1.5 1.4

1979 107 97 0.4 0.5 1.5 1.2

1980 85 93 0.8 0.6 1.2 1.1

1981 68 70 0.4 0.5 1.0 0.8

1982 77 72 0.7 0.6 1.1 0.9

1983 79 57 1.0 0.4 1.1 0.7

1984 68 61 0.8 0.4 0.9 0.7

1985 65 54 0.5 0.6 0.9 0.6

1986 55 50 0.4 0.3 0.7 0.6

1987 47 51 0.4 0.4 0.6 0.6

1988 56 50 0.3 0.3 0.7 0.6

1989 49 41 0.6 0.4 0.6 0.5

1990 42 42 0.5 1.3 0.6 0.5

1991 54 33 0.8 0.4 0.7 0.4

1992 38 34 0.2 0.2 0.5 0.4

1993 37 43 0.3 0.4 0.5 0.5

1994 44 42 0.4 0.2 0.6 0.5

1995 39 37 0.1 0.1 0.6 0.4

1996 42 46 0.2 0.5 0.6 0.6

1997 41 36 0.4 0.3 0.6 0.5

1998 48 36 0.7 0.3 0.7 0.5

1999² 44 44 0.2 0.4 0.7 0.6

¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years.
² Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.4S Standard Errors of Estimated Annual Age-Gender Specific Incidence Rates of First Use (Per 1,000 Person-Years of Exposure) of Persons Who First Used Marijuana During the Years 1965 to 1999

Year Age-Gender Specific Incidence Rates¹

Males
12-14 Females
12-14 Males
15-17 Females
15-17 Males
18-20 Females
18-20 Males
21+ Females
21+

1965 3.3 * 7.9 2.7 4.9 5.6 0.9 1.1

1966 3.9 * 8.0 5.5 15.0 7.5 1.7 1.3

1967 5.7 4.2 7.5 4.9 11.9 6.5 2.4 1.1

1968 4.7 2.5 9.0 4.4 18.4 8.3 2.6 1.5

1969 4.4 3.8 12.1 7.2 18.4 10.1 1.8 1.8

1970 5.9 6.5 12.1 8.9 16.4 9.1 2.2 1.4

1971 8.0 6.4 11.1 7.3 17.5 8.9 2.1 1.8

1972 7.9 4.6 16.1 10.4 14.8 8.8 1.9 1.5

1973 8.0 5.5 12.8 8.3 15.3 9.1 2.0 1.5

1974 6.6 7.0 14.2 10.1 12.7 10.5 1.6 1.3

1975 6.9 8.2 11.9 10.8 15.8 9.3 1.4 1.5

1976 6.0 5.7 17.5 12.4 16.5 10.4 1.6 1.4

1977 7.6 6.1 14.2 12.9 16.7 12.5 1.4 1.1

1978 7.5 6.8 16.0 13.5 13.3 13.1 1.3 1.2

1979 8.2 5.1 14.3 13.4 19.8 11.0 1.0 1.0

1980 4.9 3.7 13.9 11.2 11.2 13.1 1.3 1.0

1981 4.6 3.4 10.4 8.1 10.9 10.3 0.8 0.8

1982 4.6 3.3 9.2 7.9 11.8 10.3 1.2 0.9

1983 4.8 3.4 9.1 6.2 9.8 7.5 1.5 0.5

1984 5.5 3.8 8.0 6.6 9.8 6.8 1.0 0.8

1985 5.0 3.8 7.8 6.5 8.7 6.8 1.0 0.5

1986 4.1 3.5 7.5 6.9 8.0 5.6 0.7 0.5

1987 2.5 2.9 7.7 6.9 8.2 5.9 0.5 0.5

1988 3.1 1.8 8.7 6.8 7.1 5.1 0.7 0.6

1989 2.5 1.9 8.2 5.7 6.9 5.8 0.6 0.4

1990 2.5 2.1 7.3 4.4 7.1 4.7 0.5 0.5

1991 3.2 1.8 5.2 4.5 7.8 5.5 0.8 0.3

1992 2.7 2.6 5.1 3.9 7.5 5.2 0.4 0.3

1993 3.0 3.0 4.7 4.9 6.8 5.1 0.4 0.4

1994 3.2 3.4 5.8 4.9 5.6 6.1 0.5 0.3

1995 3.3 2.9 5.6 4.5 5.4 5.0 0.4 0.3

1996 3.1 2.8 6.0 5.6 5.8 5.2 0.4 0.4

1997 2.9 2.8 5.5 5.1 6.9 4.6 0.4 0.3

1998 2.9 2.6 5.6 4.6 5.7 5.6 0.6 0.3

1999² 3.5 3.4 7.1 5.9 5.8 5.5 0.4 0.4

* Low precision; no estimate reported.
¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years.
² Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.5S Standard Errors of Estimated Numbers (in Thousands) of Persons Who First Used Marijuana During the Years 1965 to 1999, by Racial/Ethnic Subgroups

Year Number of Initiates (1,000s)

White Black Hispanic Asian / Pacific
Islander / Native
Hawaiian American
Indian /
Alaska Native More Than
One Race

1965 57 * * * * *

1966 102 42 * * * *

1967 111 35 22 * * *

1968 115 63 26 * * *

1969 139 37 30 * * *

1970 152 41 22 18 * 10

1971 139 46 42 * 7 *

1972 144 47 35 5 8 8

1973 148 46 24 * * *

1974 137 41 50 5 * 8

1975 137 49 34 6 * *

1976 153 53 37 * 12 *

1977 140 49 37 26 * 12

1978 141 46 44 32 * 6

1979 125 52 28 * 3 7

1980 114 43 30 * * *

1981 89 33 24 * 3 *

1982 92 32 31 * 7 3

1983 90 23 32 18 5 *

1984 80 37 16 * 3 2

1985 71 24 28 20 3 5

1986 63 26 22 8 8 6

1987 63 21 20 22 4 4

1988 66 19 26 8 10 6

1989 57 18 25 9 * 4

1990 51 21 21 16 3 2

1991 55 20 16 15 5 5

1992 46 22 18 7 4 7

1993 47 22 18 8 7 5

1994 52 25 19 7 6 5

1995 47 20 17 10 3 6

1996 53 22 21 13 4 6

1997 48 25 20 7 5 6

1998 51 19 20 12 4 6

1999¹ 54 23 21 10 8 7

¹ Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.6S Standard Errors of Estimated Mean Ages at First Use of Persons Who First Used Marijuana During the Years 1965 to 1999, by Racial/Ethnic Subgroups

Year Mean Age at First Use

White Black Hispanic Asian / Pacific
Islander / Native
Hawaiian American
Indian /
Alaska Native More Than
One Race

1965 1.5 * * * * *

1966 0.5 1.6 * * * *

1967 0.5 0.9 2.9 * * *

1968 0.5 0.8 3.0 * * *

1969 0.4 0.8 2.1 * * *

1970 0.3 1.2 0.4 0.8 * *

1971 0.4 1.7 0.8 * * *

1972 0.4 0.7 1.8 * 1.4 *

1973 0.4 1.3 1.7 * * *

1974 0.3 1.3 0.8 * * 1.0

1975 0.4 0.6 1.1 * * *

1976 0.3 1.1 0.7 * 1.0 0.6

1977 0.4 0.6 0.9 0.3 0.9 *

1978 0.4 0.6 1.7 1.4 * *

1979 0.4 0.7 0.5 * 0.8 1.0

1980 0.6 1.2 1.0 0.8 * *

1981 0.4 1.3 0.7 * * *

1982 0.5 1.7 0.6 * 2.2 *

1983 0.7 1.0 1.1 1.1 1.9 1.1

1984 0.3 2.2 0.4 7.6 2.4 1.1

1985 0.5 0.6 0.8 1.3 0.7 1.6

1986 0.3 0.5 0.7 0.4 0.5 1.4

1987 0.4 0.5 0.6 1.4 2.5 2.8

1988 0.2 0.4 1.2 1.2 2.4 0.6

1989 0.5 0.4 0.6 1.5 0.6 1.2

1990 0.8 0.7 0.9 0.7 2.2 0.8

1991 0.6 0.4 0.4 0.9 2.9 0.7

1992 0.2 0.4 0.4 0.7 0.9 0.7

1993 0.3 1.1 0.4 1.9 4.7 0.4

1994 0.3 0.3 0.3 0.4 0.5 0.6

1995 0.1 0.3 0.3 1.1 0.5 0.3

1996 0.4 0.4 0.5 0.6 0.6 0.7

1997 0.4 0.7 0.3 0.5 0.9 0.4

1998 0.6 0.3 0.3 1.0 0.8 0.9

1999¹ 0.3 0.3 0.4 1.4 0.7 0.9

* Low precision; no estimate reported.
¹ Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.7S Standard Errors of Estimated Annual Incidence Rates of First Use (Per 1,000 Person-Years of Exposure) of Persons Who First Used Marijuana During the Years 1965 to 1999, by Racial/Ethnic Subgroups

Year Racial/Ethnic Specific Incidence Rates¹

White Black Hispanic Asian / Pacific
Islander / Native
Hawaiian American
Indian /
Alaska Native More Than
One Race

1965 0.5 * * * * *

1966 1.0 3.0 * * * *

1967 1.0 2.4 1.8 * * *

1968 1.0 4.2 2.0 * * *

1969 1.2 2.5 2.3 * * *

1970 1.4 2.6 1.7 3.5 * 10.6

1971 1.2 3.0 3.0 * 9.9 *

1972 1.3 3.0 2.4 0.8 12.3 8.0

1973 1.3 2.9 1.6 * * *

1974 1.2 2.6 3.3 0.9 * 7.7

1975 1.2 3.0 2.3 0.9 * *

1976 1.4 3.2 2.4 * 15.9 16.9

1977 1.3 3.0 2.3 4.1 * 11.5

1978 1.2 2.8 2.7 5.1 * 5.4

1979 1.1 3.1 1.6 * 4.2 6.4

1980 1.0 2.5 1.8 * * *

1981 0.8 1.9 1.4 * * *

1982 0.8 1.8 1.7 * 9.3 2.8

1983 0.8 1.3 1.7 2.7 6.4 *

1984 0.7 2.0 0.9 * 4.2 2.0

1985 0.6 1.2 1.5 2.8 3.9 3.8

1986 0.5 1.4 1.1 1.1 9.9 4.3

1987 0.5 1.1 1.0 2.9 5.1 3.1

1988 0.6 1.0 1.3 1.1 12.3 4.2

1989 0.5 0.9 1.3 1.2 * 3.2

1990 0.4 1.1 1.1 2.2 3.9 1.3

1991 0.5 1.0 0.8 2.1 6.9 3.6

1992 0.4 1.1 0.9 1.0 5.3 5.4

1993 0.4 1.2 0.9 1.2 9.2 3.9

1994 0.5 1.3 1.1 1.1 7.7 3.9

1995 0.4 1.1 1.0 1.4 4.4 4.7

1996 0.5 1.2 1.2 1.9 5.2 5.2

1997 0.5 1.4 1.1 1.0 6.7 5.0

1998 0.5 1.1 1.1 1.7 6.3 5.2

1999² 0.5 1.3 1.2 1.4 14.8 6.8

* Low precision; no estimate reported.
¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years.
² Estimated using 2000 data only.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 6.1S Standard Errors and Suppression Rule for Percentages with Lifetime and Past Year Use of Heroin, Cocaine, and Psychotherapeutics among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 1999 and 2000

Age
in
Years Age of
Marijuana
Initiation in
Years Heroin Cocaine Any Psychotherapeutic

Lifetime Past Year Lifetime Past Year Lifetime Past Year

Standard
Error Suppression¹ Standard
Error Suppression¹ Standard
Error Suppression¹ Standard
Error Suppression¹ Standard
Error Suppression¹ Standard
Error Suppression¹

Total 14 or younger 0.81 0 0.23 0 1.28 0 0.63 0 1.24 0 0.84 0

15-17 0.43 0 0.08 0 0.89 0 0.31 0 0.89 0 0.40 0

18-20 0.46 0 0.07 0 1.06 0 0.32 0 1.00 0 0.45 0

21 or older 0.35 0 0.11 0 0.94 0 0.18 0 1.09 0 0.37 0

Never used marijuana 0.02 0 0.00 0 0.06 0 0.01 0 0.20 0 0.10 0

26-34 14 or younger 0.62 0 0.05 0 1.39 0 0.82 0 1.39 0 0.85 0

15-17 0.37 0 0.14 0 0.97 0 0.44 0 0.96 0 0.54 0

18-20 0.29 0 0.07 0 1.17 0 0.41 0 1.16 0 0.60 0

21 or older 0.41 0 0.00 1 1.53 0 0.43 0 1.54 0 0.79 0

Never used marijuana 0.03 0 0.01 0 0.12 0 0.03 0 0.32 0 0.17 0

35-49 14 or younger 1.24 0 0.39 0 1.85 0 0.88 0 1.89 0 1.28 0

15-17 0.56 0 0.10 0 1.26 0 0.40 0 1.23 0 0.55 0

18-20 0.57 0 0.10 0 1.45 0 0.40 0 1.29 0 0.56 0

21 or older 0.35 0 0.30 0 1.58 0 0.47 0 1.51 0 0.61 0

Never used marijuana 0.05 0 0.00 1 0.17 0 0.04 0 0.38 0 0.19 0

50+ 17 or younger 5.27 1 0.00 1 6.69 1 2.94 1 6.64 1 2.33 1

18-20 1.79 0 0.19 0 3.50 0 1.09 0 3.20 0 1.56 0

21 or older 0.65 0 0.00 1 1.39 0 0.10 0 1.78 0 0.55 0

Never used marijuana 0.02 0 0.01 0 0.06 0 0.01 0 0.27 0 0.14 0

Note: Nonmedical use of any prescription-type psychotherapeutic indicates using pain relievers, tranquilizers, stimulants, or sedatives at least once. Indicated use does not include over-the-counter drugs.
¹ 1 = estimate should be suppressed due to low precision based either on small sample size or extreme variance; 0 = no suppression.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 6.2S Standard Errors and Suppression Rule for Percentages with Past Year Heavy Marijuana Use and Heavy Use of Other Illicit Drugs among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 1999 and 2000

Age in Years Age of Marijuana
Initiation in Years Heavy Marijuana Use Heavy Use of Other Illicit
Drugs

Standard Error Suppression¹ Standard Error Suppression¹

Total 14 or younger
0.51
0 0.61 0

15-17
0.17
0 0.29 0

18-20
0.12
0 0.28 0

21 or older
0.21
0 0.21 0

Never used marijuana
0.00
1 0.06 0

26-34 14 or younger
0.79
0 0.75 0

15-17
0.28
0 0.40 0

18-20
0.30
0 0.31 0

21 or older
0.25
0 0.49 0

Never used marijuana
0.00
1 0.10 0

35-49 14 or younger
0.64
0 0.86 0

15-17
0.22
0 0.37 0

18-20
0.14
0 0.42 0

21 or older
0.38
0 0.49 0

Never used marijuana
0.00
1 0.12 0

50+ 17 or younger
0.00
1 2.84 0

18-20
0.12
0 0.52 0

21 or older
0.30
0 0.20 0

Never used marijuana
0.00
1 0.09 0

Note: Heavy marijuana use refers to using marijuana on 300 or more days in the past year. Heavy use of other illicit drugs refers to using cocaine, hallucinogens, inhalants, heroin, or any prescription-type psychotherapeutic used nonmedically (i.e., pain relievers, sedatives, tranquilizers, or stimulants) on at least 50 days in the past year.
¹ 1 = estimate should be suppressed because of low precision based either on small sample size or extreme variance; 0 = no suppression.
Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 6.3S Standard Errors and Suppression Rule for Percentages with Past Year Alcohol and/or Illicit Drug Dependence or Abuse among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 2000
Age in Years	Age of Marijuana Initiation in Years	Illicit Drug Dependence or Abuse		Alcohol or Illicit Drug Dependence or Abuse		Alcohol Dependence		Illicit Drug Dependence		Marijuana Dependence		Other Illicit Drug Dependence
Age in Years	Age of Marijuana Initiation in Years	Standard Error	Suppression¹	Standard Error	Suppression¹	Standard Error	Suppression¹	Standard Error	Suppression¹	Standard Error	Suppresssion¹	Standard Error	Suppression¹
Total	14 or younger	0.84	0	1.28	0	0.78	0	0.73	0	0.58	0	0.55	0
	15-17	0.36	0	0.67	0	0.43	0	0.25	0	0.19	0	0.19	0
	18-20	0.48	0	0.75	0	0.60	0	0.47	0	0.25	0	0.43	0
	21 or older	0.33	0	0.91	0	0.65	0	0.25	0	0.13	0	0.21	0
	Never used marijuana	0.04	0	0.17	0	0.12	0	0.04	0	0.00	1	0.04	0
26-34	14 or younger	1.02	0	1.48	0	0.87	0	0.90	0	0.73	0	0.58	0
	15-17	0.47	0	0.98	0	0.60	0	0.34	0	0.20	0	0.31	0
	18-20	0.42	0	1.23	0	0.77	0	0.29	0	0.19	0	0.25	0
	21 or older	1.07	0	1.99	0	1.17	0	0.47	0	0.47	0	0.07	0
	Never used marijuana	0.11	0	0.31	0	0.18	0	0.10	0	0.00	1	0.10	0
35-49	14 or younger	1.13	0	1.85	0	1.08	0	0.97	0	0.79	0	0.70	0
	15-17	0.38	0	0.86	0	0.59	0	0.35	0	0.27	0	0.25	0
	18-20	0.58	0	1.01	0	0.77	0	0.57	0	0.40	0	0.47	0
	21 or older	0.69	0	1.48	0	1.13	0	0.57	0	0.00	1	0.57	0
	Never used marijuana	0.10	0	0.37	0	0.28	0	0.10	0	0.00	1	0.10	0
50+	17 or younger	5.30	1	5.37	1	3.29	1	3.15	1	0.00	1	3.15	0
	18-20	1.76	1	2.12	0	1.85	0	1.71	1	0.34	0	1.71	0
	21 or older	0.29	0	1.29	0	0.92	0	0.28	0	0.22	0	0.16	0
	Never used marijuana	0.05	0	0.24	0	0.15	0	0.04	0	0.00	1	0.04	0
Note: Illicit drug dependence or abuse indicates dependence on or abuse of at least one of the following drugs: marijuana/hashish, cocaine (including crack), heroin, hallucinogens (including LSD and PCP), inhalants, or any prescription-type psychotherapeutic used nonmedically. Other illicit drug dependence indicates meeting the dependence criteria of at least one of the following drugs: cocaine, hallucinogens, inhalants, heroin, pain relievers, sedatives, tranquilizers, or stimulants. Dependence or abuse is based on the definition found in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). ¹ 1 = estimate should be suppressed because of low precision based either on small sample size or extreme variance; 0 = no suppression. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 2000.

This page was last updated on June 16, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.

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Table 3.1S Standard Errors of Estimated Numbers (in Thousands) of Persons Who First Used Marijuana During the Years 1965 to 1999, Their Mean Age at First Use, and the Annual Incidence Rates of First Use (Per 1,000 Person-Years of Exposure), for All Ages
Year	Number of Initiates (1,000s)	Mean Age at First Use	Incidence Rates¹
1965	75	1.2	0.5
1966	114	0.5	0.8
1967	119	0.4	0.8
1968	136	0.4	0.9
1969	147	0.3	1.0
1970	164	0.3	1.1
1971	158	0.3	1.0
1972	157	0.3	1.0
1973	154	0.4	1.0
1974	150	0.3	1.0
1975	150	0.4	1.0
1976	163	0.3	1.1
1977	157	0.3	1.0
1978	162	0.3	1.0
1979	144	0.3	1.0
1980	127	0.5	0.8
1981	97	0.3	0.6
1982	101	0.5	0.6
1983	101	0.6	0.6
1984	95	0.4	0.6
1985	85	0.4	0.5
1986	74	0.3	0.4
1987	71	0.3	0.4
1988	73	0.2	0.4
1989	67	0.4	0.4
1990	59	0.6	0.4
1991	62	0.5	0.4
1992	54	0.2	0.3
1993	58	0.3	0.4
1994	63	0.2	0.4
1995	56	0.1	0.4
1996	66	0.3	0.4
1997	59	0.3	0.4
1998	61	0.4	0.4
1999²	61	0.2	0.4
¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years. ² Estimated using 2000 data only. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.4S Standard Errors of Estimated Annual Age-Gender Specific Incidence Rates of First Use (Per 1,000 Person-Years of Exposure) of Persons Who First Used Marijuana During the Years 1965 to 1999
Year	Age-Gender Specific Incidence Rates¹
Year	Males 12-14	Females 12-14	Males 15-17	Females 15-17	Males 18-20	Females 18-20	Males 21+	Females 21+
1965	3.3	*	7.9	2.7	4.9	5.6	0.9	1.1
1966	3.9	*	8.0	5.5	15.0	7.5	1.7	1.3
1967	5.7	4.2	7.5	4.9	11.9	6.5	2.4	1.1
1968	4.7	2.5	9.0	4.4	18.4	8.3	2.6	1.5
1969	4.4	3.8	12.1	7.2	18.4	10.1	1.8	1.8
1970	5.9	6.5	12.1	8.9	16.4	9.1	2.2	1.4
1971	8.0	6.4	11.1	7.3	17.5	8.9	2.1	1.8
1972	7.9	4.6	16.1	10.4	14.8	8.8	1.9	1.5
1973	8.0	5.5	12.8	8.3	15.3	9.1	2.0	1.5
1974	6.6	7.0	14.2	10.1	12.7	10.5	1.6	1.3
1975	6.9	8.2	11.9	10.8	15.8	9.3	1.4	1.5
1976	6.0	5.7	17.5	12.4	16.5	10.4	1.6	1.4
1977	7.6	6.1	14.2	12.9	16.7	12.5	1.4	1.1
1978	7.5	6.8	16.0	13.5	13.3	13.1	1.3	1.2
1979	8.2	5.1	14.3	13.4	19.8	11.0	1.0	1.0
1980	4.9	3.7	13.9	11.2	11.2	13.1	1.3	1.0
1981	4.6	3.4	10.4	8.1	10.9	10.3	0.8	0.8
1982	4.6	3.3	9.2	7.9	11.8	10.3	1.2	0.9
1983	4.8	3.4	9.1	6.2	9.8	7.5	1.5	0.5
1984	5.5	3.8	8.0	6.6	9.8	6.8	1.0	0.8
1985	5.0	3.8	7.8	6.5	8.7	6.8	1.0	0.5
1986	4.1	3.5	7.5	6.9	8.0	5.6	0.7	0.5
1987	2.5	2.9	7.7	6.9	8.2	5.9	0.5	0.5
1988	3.1	1.8	8.7	6.8	7.1	5.1	0.7	0.6
1989	2.5	1.9	8.2	5.7	6.9	5.8	0.6	0.4
1990	2.5	2.1	7.3	4.4	7.1	4.7	0.5	0.5
1991	3.2	1.8	5.2	4.5	7.8	5.5	0.8	0.3
1992	2.7	2.6	5.1	3.9	7.5	5.2	0.4	0.3
1993	3.0	3.0	4.7	4.9	6.8	5.1	0.4	0.4
1994	3.2	3.4	5.8	4.9	5.6	6.1	0.5	0.3
1995	3.3	2.9	5.6	4.5	5.4	5.0	0.4	0.3
1996	3.1	2.8	6.0	5.6	5.8	5.2	0.4	0.4
1997	2.9	2.8	5.5	5.1	6.9	4.6	0.4	0.3
1998	2.9	2.6	5.6	4.6	5.7	5.6	0.6	0.3
1999²	3.5	3.4	7.1	5.9	5.8	5.5	0.4	0.4
* Low precision; no estimate reported. ¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years. ² Estimated using 2000 data only. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 3.7S Standard Errors of Estimated Annual Incidence Rates of First Use (Per 1,000 Person-Years of Exposure) of Persons Who First Used Marijuana During the Years 1965 to 1999, by Racial/Ethnic Subgroups
Year	Racial/Ethnic Specific Incidence Rates¹
Year	White	Black	Hispanic	Asian / Pacific Islander / Native Hawaiian	American Indian / Alaska Native	More Than One Race
1965	0.5	*	*	*	*	*
1966	1.0	3.0	*	*	*	*
1967	1.0	2.4	1.8	*	*	*
1968	1.0	4.2	2.0	*	*	*
1969	1.2	2.5	2.3	*	*	*
1970	1.4	2.6	1.7	3.5	*	10.6
1971	1.2	3.0	3.0	*	9.9	*
1972	1.3	3.0	2.4	0.8	12.3	8.0
1973	1.3	2.9	1.6	*	*	*
1974	1.2	2.6	3.3	0.9	*	7.7
1975	1.2	3.0	2.3	0.9	*	*
1976	1.4	3.2	2.4	*	15.9	16.9
1977	1.3	3.0	2.3	4.1	*	11.5
1978	1.2	2.8	2.7	5.1	*	5.4
1979	1.1	3.1	1.6	*	4.2	6.4
1980	1.0	2.5	1.8	*	*	*
1981	0.8	1.9	1.4	*	*	*
1982	0.8	1.8	1.7	*	9.3	2.8
1983	0.8	1.3	1.7	2.7	6.4	*
1984	0.7	2.0	0.9	*	4.2	2.0
1985	0.6	1.2	1.5	2.8	3.9	3.8
1986	0.5	1.4	1.1	1.1	9.9	4.3
1987	0.5	1.1	1.0	2.9	5.1	3.1
1988	0.6	1.0	1.3	1.1	12.3	4.2
1989	0.5	0.9	1.3	1.2	*	3.2
1990	0.4	1.1	1.1	2.2	3.9	1.3
1991	0.5	1.0	0.8	2.1	6.9	3.6
1992	0.4	1.1	0.9	1.0	5.3	5.4
1993	0.4	1.2	0.9	1.2	9.2	3.9
1994	0.5	1.3	1.1	1.1	7.7	3.9
1995	0.4	1.1	1.0	1.4	4.4	4.7
1996	0.5	1.2	1.2	1.9	5.2	5.2
1997	0.5	1.4	1.1	1.0	6.7	5.0
1998	0.5	1.1	1.1	1.7	6.3	5.2
1999²	0.5	1.3	1.2	1.4	14.8	6.8
* Low precision; no estimate reported. ¹ The numerator of each rate is the number of persons who first used marijuana in the year, while the denominator is the person-time exposure measured in thousands of years. ² Estimated using 2000 data only. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.

Table 6.2S Standard Errors and Suppression Rule for Percentages with Past Year Heavy Marijuana Use and Heavy Use of Other Illicit Drugs among Adults Aged 26 or Older, by Age at First Marijuana Use and Age Groups: 1999 and 2000
Age in Years	Age of Marijuana Initiation in Years	Heavy Marijuana Use		Heavy Use of Other Illicit Drugs
Age in Years	Age of Marijuana Initiation in Years	Standard Error	Suppression¹	Standard Error	Suppression¹
Total	14 or younger	0.51	0	0.61	0
	15-17	0.17	0	0.29	0
	18-20	0.12	0	0.28	0
	21 or older	0.21	0	0.21	0
	Never used marijuana	0.00	1	0.06	0
26-34	14 or younger	0.79	0	0.75	0
	15-17	0.28	0	0.40	0
	18-20	0.30	0	0.31	0
	21 or older	0.25	0	0.49	0
	Never used marijuana	0.00	1	0.10	0
35-49	14 or younger	0.64	0	0.86	0
	15-17	0.22	0	0.37	0
	18-20	0.14	0	0.42	0
	21 or older	0.38	0	0.49	0
	Never used marijuana	0.00	1	0.12	0
50+	17 or younger	0.00	1	2.84	0
	18-20	0.12	0	0.52	0
	21 or older	0.30	0	0.20	0
	Never used marijuana	0.00	1	0.09	0
Note: Heavy marijuana use refers to using marijuana on 300 or more days in the past year. Heavy use of other illicit drugs refers to using cocaine, hallucinogens, inhalants, heroin, or any prescription-type psychotherapeutic used nonmedically (i.e., pain relievers, sedatives, tranquilizers, or stimulants) on at least 50 days in the past year. ¹ 1 = estimate should be suppressed because of low precision based either on small sample size or extreme variance; 0 = no suppression. Source: SAMHSA, Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.