This is my own chart—showing the dramatic changes in the average incomes of the bottom 90 percent, the top 10 percent, and the top 1 percent—from the World Wealth and Income Database.
Incomes are in thousands of real 2015 dollars. Thus, for example, the average income of the bottom 90 percent fell between 1979 and 2015 (from $34.6 thousand to $33.2 thousand), while the average income of the top 10 percent rose (from $149.1 thousand to $273.8 thousand) and that of the top 1 percent soared (from $370.2 thousand to over $1 million).
Emmanuel Saez, Thomas Piketty, and the rest of the team need to be credited for making their data available. Readers should feel free to use this chart and reproduce it as they wish. . .