By 2020, One Quarter of the Labor Force Will Be 55-and-older
"In 1990, 11.9 percent of the labor force was 55 years and older. Over the 1990-2000 timeframe, the share of the older labor force increased to 13.1 percent. In 2010, the share increased again, to 19.5 percent. BLS projects that the share of the 55-years-and-older labor force will increase to 25.2 percent in 2020," according to a 2012 analysis of census data by the Bureau of Labor Statistics.
Toossi, M. (2012). Labor force projections to 2020: A more slowly growing workforce. Monthly Labor Review, 135(1), 43-49. Retrieved from bls.gov.