On the other side of the macroeconomic coin, despite the standard political back-and-forth [1], government spending has also remained basically constant at 21% of GDP for the last few decades.
[1] Thinking of the Democrats and Republicans as countervaling processes maintaining a homeostatic equilibrium that expresses the electorate's preference for a government that spends 20% of GDP is a good way to rehabilitate yourself if you've picked up the vice of excessive political involvement.
But now that may be changing:
http://www.marginalrevolution.com/marginalrevolution/2009/02...
[1] Thinking of the Democrats and Republicans as countervaling processes maintaining a homeostatic equilibrium that expresses the electorate's preference for a government that spends 20% of GDP is a good way to rehabilitate yourself if you've picked up the vice of excessive political involvement.