The NCI procures and maintains U.S. population data for the denominators of cancer incidence and mortality rates. Annual mid-year population estimates stratified by age, gender, bridged race, and Hispanic ethnicity are available at county and census tract levels. These are also referred to as "July 1st Populations," which have incorporated migration data and represent average populations in a year. They differ from "April 1st populations" published by the Census Bureau, which are solely based on information collected in the Decennial Censuses and represent a snapshot of the U.S. as of April 1st.

U.S. County Population Data

The bridged race county population estimates are produced under a collaborative arrangement between the U. S. Census Bureau and the National Center for Health Statistics with support from NCI through an interagency agreement, except for 2010-2019 intercensal population estimates that are produced by Woods & Poole Economics, Inc. through a contract with NCI. Slightly modified county population estimates, which only affect estimates for the state of Hawaii, are used in SEER*Stat software and available for download as text files.

End of Decade Population Changes

In the April 2024 data release, NCI will use bridged race population estimates produced using information from Census 2020. Since this is the first year using populations basing off Census 2020, some changes in the populations may exist this year compared to past years.

U.S. Census Tract Population Data

The bridged race census tract population estimates are produced by Woods & Poole Economics, Inc. (W&P) with support from NCI through a contract with methodology jointly developed by NCI, W&P, and the North American Association of Central Cancer Registries (NAACCR). Text data files and SEER*Stat databases are available for download to anyone who requests them and agrees to certain standard data use conditions.