The Census Bureau updates the population figures from the decennial census of population and housing by issuing estimates in intervening years. The methods employed to make these estimates include the use of administrative records, such as those maintained by the U.S. Social Security Administration and the National Center for Health Statistics.
The Census Bureau also issues population projections. In large part, these projections are made by the use of statistical methods. These population estimates and projections are available in reports and data files. The data files are available at the Census Bureau internet site under the Estimates and Projections areas.