In comments, a complaint was lodged that I used a graph with a linear y-axis for demonstrating change in income over the past 40 years. The problem with such a graph is that if everyone has the same percentage income growth, the slope for high income earners will still look higher.
So here is a graph where the y-axis is logarithmic. It also contains more recent data:
The point doesn't change: from 1969 until 2010, income at the top of the bottom quintile essentially hasn't moved (it changed from 26,289 to 26,685). Income at the bottom of the top five percent has moved quite a lot (from 121,516 to 200,354) .
So here is a graph where the y-axis is logarithmic. It also contains more recent data:
