The series comes from the 'Current Population Survey (Household Survey)'
The source code is: LNU00024230
Source: US. Bureau of Labor Statistics
Release: Employment Situation
US. Bureau of Labor Statistics, Civilian Noninstitutional Population - 55 years and over [LNU00024230], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/LNU00024230/, August 31, 2015.