January 29, 2014
Post war until roughly the 1970s, increases in income in all quintiles more or less moved together. The bottom quintile increased with the top quintile. Since the 70s, the top two quintiles continued to grow, with the top quintile actually accelerating (although to be fair, it corrected/adjusted during the Great Recession, but only modestly). But since the 1970s, the bottom three quintiles have been pretty much flat.