Annual Population Estimates for the United States, States, Metropolitan Statistical Areas, Micropolitan Statistical Areas, Counties, Incorporated Places, and Minor Civil Divisions; and for Puerto Rico and Its Municipios // Source: U.S. Census Bureau, Population Division // The contents of this file are released on a rolling basis from December through May. // The estimates are developed from an April 1, 2020 base population and may incorporate changes resulting from the Count Question Resolution program and/or geographic program revisions. // The Office of Management and Budget's statistical area delineations for metropolitan, micropolitan, and combined statistical areas, as well as metropolitan divisions, are those issued by that agency. // Current data on births, deaths, and migration are used to calculate population change since April 1, 2020. An annual time series of estimates is produced, beginning with April 1, 2020 and extending to the vintage year. The vintage year refers to the final year of the time series. The reference date for all estimates is July 1, unless otherwise specified. With each new issue of estimates, the entire estimates series is revised. Additional information, including historical and intercensal estimates, evaluation estimates, demographic analysis, research papers, and methodology is available on website: https://www.census.gov/programs-surveys/popest.html.