The US Bureau of Labor Statistics publishes the headline unemployment rate. They also report a few flavors of Labor participation data, including the Civilian Labor Force Participation Rate. That rate is basically what you are talking about, and the number aren’t pretty. If that rate isn’t exactly what you want, there are a dozen other variants.
The numbers are reported, generally pretty good, and mostly ignored by media and the public. Go to BLS.gov
Thanks for the suggestion! Table here
More interesting parts:
Males, 25-54, has gone down from 1994 to 2014, 91.7% to 88.2. That's 11.8% of the "prime working age" male labor force that is not employed.
Of the "65 and older" set, labor force participation has gone up from 16.9% to 23.0, indicating that more men are having difficulty making ends meet on just retirement income (pension, 401K)