Population ages 65 and above as a percentage of the total population. Population is based on the de facto definition of population, which counts all residents regardless of legal status or citizenship--except for refugees not permanently settled in the country of asylum, who are generally considered part of the population of the country of origin.
World Bank Source: The United Nations Population Division's World Population Prospects.
Source Indicator: SP.POP.65UP.TO.ZS
Source: World Bank
Release: World Development Indicators
World Bank, Population ages 65 and above for the United States [SPPOP65UPTOZSUSA], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/SPPOP65UPTOZSUSA, May 3, 2016.
FRED BlogChanging demographics