National Level - age data are available from the following sources
- Censuses - These data are from the decennial censuses taken every ten years.
- Estimates - These data are produced for each year between censuses
- Surveys - These data are from various surveys, usually conducted on an annual basis, including the American Community Survey (ACS) and the Current Population Survey (CPS).
- Projections - These data illustrate the population for future years, based on plausible courses
of population change (births, deaths, and international migration).