Annual Intercensal Population Estimates for United States, States, Counties, and Subcounty Places, and for Puerto Rico and Its Municipios: April 1, 2000 to April 1, 2010 // Source: U.S. Census Bureau, Population Division // Note: The April 1, 2000 Population Estimates base reflects changes to the Census 2000 population from the Count Question Resolution program and geographic program revisions. // For detailed information about the methods used to create the intercensal estimates, see https://www.census.gov/popest/methodology/index.html. // The intercensal estimates for 2000-2010 for the United States and Puerto Rico populations are produced by the Census Bureau's Population Estimates Program by modifying the 2000-2010 postcensal estimates prepared previously for the United States and Puerto Rico, to account for differences between the postcensal estimates for April 1, 2010 and the 2010 Census counts. The reference date for all estimates is July 1, unless otherwise specified. The Population Estimates Program provides additional information including historical and current estimates, evaluation estimates, demographic analysis, and research papers on its website: https://www.census.gov/popest/index.html