The graph depicts the number of Amerians employed by government (presumably federal + state and local) in red, versus those employed in manufacturing and construction in blue, over the time period 1969 - 2008.
I don't have access to the primary data, which was compiled and graphed at a subscription-only website, linked here, but it's probably valid. The blue line of course represents only a part of the private sector, but the trends are obvious.
I won't editorialize, except to note that this is not a reflection of Republican policy or Democratic policy - its a bipartisan accomplishment. Government begets more government.
This is a complex subject that deserves more than a casual comment, but the graph is striking and I wanted to offer it for your consideration.