The proportion of U.S. adults who are “in the labor force”–that is, who either have jobs or are unemployed and looking for a job–has been falling for a decade, as I explored in an April 26, 2012, post on “Falling Labor Force Participation.” But for one demographic group, the elderly, labor force participation is rising substantially.
He cites a Census Bureau Study. This is a two-decade trend, and I think that the most plausible explanation is better health for those in the 65-75 age bracket.