
What's interesting isn't just the raw numbers, deplorable as they may be, but the volatility. There are a couple things of note here. First of all, obviously, the top one percent grab a much higher share of income under a more laissez-faire, pro-business style of government like we have in the 1920s or today. But at the same time, their share is much more cyclical. The crash of 1929 is clearly visible on the chart, as is the post-Internet bubble/9-11/Enron et al market trough. But the recession of the late '60s is just a blip, and the early-80s crash doesn't show up at all. Presumably, the income of the highest percentile is much more heavily dependent on stocks and other cyclical investments, so it falls quickly relative to the other 99.