The Congressional Budget Office has found that between 1979 and 2007, the top 1 percent of households saw their inflation-adjusted income grow 275 percent. For the bottom 20 percent, it grew just 18 percent, and federal tax and transfer programs also did less and less to reduce income inequality over that period.
The mounting concentration of wealth is even more dramatic. A recent Economic Policy Institute study found that between 1983 and 2010 about three-quarters of all new wealth accrued to the wealthiest 5 percent of households. Over the same period, the bottom 60 percent actually became poorer.
As someone who was a Libertarian (yes, capital "L") for most of that time, I wonder sometimes if we were wrong about all that "trickle down" stuff. It didn't work very well, did it?