One picture is worth...

The Labor Force Participation Rate measures the percentage of the working-age population who is either 1) employed; or 2) in the government system as looking for work. It does not measure those who have given up looking for work. That means, of course, that millions of discouraged workers without jobs are not officially counted as unemployed, even though they are in fact "unemployed." 

Paradoxically, the more unemployed people who quit looking for work, the lower the official government unemployment rate. 

Here, then, is the historic trend of the LFPR since Barack Obama took office. See if you notice a trend.

Labor Force Participation Rate since January, 2009

And this is why the unemployment rate under Barack Obama has managed to stay under ten percent, despite there being ten million more Americans without jobs than when he took office. (Today's false number, 6.6%)