This report represents estimates for months back to April 1,1990, of (1) resident population plus Armed Forces overseas, (2) resident population, and (3) civilian population.  The estimates are based on data from the decennial census; statistics on births and deaths provided by the National Center for Health Statistics, U.S. Public Health Service; statistics on immigration provided by the Immigration and Naturalization Service, Department of Justice; data on Federal civilian employees abroad and their dependents provided by the Department of Defense and the Office of Personnel Management; data on movement between Puerto Rico and the 50 States (including the District of Columbia) provided by the Puerto Rico Planning Board; and data on the Armed Forces provided by the Department of Defense.  For a discussion of the estimating procedure used in deriving these estimates, see Current Population Reports, P25-1045.