 Since the late 1970s, inequality of income in America has gotten worse across the board, but it's at the top where income has become most concentrated — concentrated at a level not seen since just before the Great Depression.Most of the gains of economic growth since the 1970s have gone to the top 1% of Americans, and most of that to the top 0.1%.While the share of America's income gains between 1979 and 2005 for the bottom middle- and lower-income 60% of the population was just 13.5% (and most of that gain came from working longer hours), the top 0.1% share was over 20%.