From a post of John Stossel "President Obama touts, "The lowest unemployment rate in over five years," but it's only because many gave up work. The percent of people employed is flat"
I tried to find another source for this. I found this.
There must be a total people who are employable statistic somewhere. That should be able to get you the Stossel graph.
From the Bureau of Labor Statistics
Labor Force Statistics from the Current Population Survey
Series Id: LNS11300000
Series title: (Seas) Labor Force Participation Rate
Labor force status: Civilian labor force participation rate
Type of data: Percent or rate
Age: 16 years and over