The population estimates displayed in Easy Access to Juvenile Populations were derived from data originally collected by the U.S. Census Bureau and subsequently modified by the National Center for Health Statistics (NCHS).

The citation for the 1990 to 1999 data files is:

National Center for Health Statistics (2004). Bridged-race intercensal estimates of the July 1, 1990-July 1, 1999 United States resident population by county, single-year of age, sex, race, and Hispanic origin. [Released 7/26/2004; Retrieved 9/15/2004]. Prepared by the U.S. Census Bureau with support from the National Cancer Institute. Available online from http://www.cdc.gov/nchs/about/major/dvs/popbridge/popbridge.htm.

The citation for the 2000 to 2006 data files is:

National Center for Health Statistics (2007). Estimates of the July 1, 2000-July 1, 2006, United States resident population from the Vintage 2006 postcensal series by year, county, age, sex, race, and Hispanic origin. [Released 8/16/2007; Retrieved 9/12/2007]. Prepared under a collaborative arrangement with the U.S. Census Bureau. Available online from http://www.cdc.gov/nchs/about/major/dvs/popbridge/popbridge.htm.

Users interested in how these data files were prepared should consult the United States Census 2000 Population with Bridge Race Categories report, available as a PDF file from http://www.cdc.gov/nchs/data/series/sr_02/sr02_135.pdf.