Services data has gone through many changes over the years. What is now the Service Annual Survey was three separate surveys the Transportation Annual Survey, Annual Survey of Communication Services, and Service Annual Survey. These three surveys were collected under the U.S. Standard Industrial Classification (SIC) until 1998. Beginning with the 1999 survey year, data will be published on a North American Industry Classification System (NAICS) basis for 1999 and 1998. The 1998 survey year was the final year the U.S. Census Bureau published data for its annual service surveys using the Standard Industrial Classification (SIC) System. These SIC based data are not comparable to NAICS. NAICS was developed jointly by the United States, Canada, and Mexico to provide new comparability in statistics about business activity across North America. The following URL contains detailed information about NAICS and provides a comparison of the SIC and NAICS systems: http://www.census.gov/epcd/www/naics.html