Jordan Weissmann at The Atlantic points us to a noteworthy breakdown of income changes through the years.

 

The Rich Get Poorer, The Poor Get Poorer

 

This tells a pretty interesting story. Coming out of World War II, the gains in the bottom decile are pretty solid up until the 1970s, when they seem to stagnate along with all other income groups.  It isn’t until the  1980s and 1990s that the top income bracket really takes off.

There are, of course, dozens of caveats with data like these.  But those aside, data guru Andrew Gelman simply doesn’t like this plot, so he takes some pains to make this clearer.  Here’s Gelman’s discussion, and below you can see roughly the same data in a more conventional time series format.

 

As Gelman correctly points out, his full series tells a different story. In particular, the sharp income decrease of the last decade occurred principally since 2007.  Yikes.

Gelman is great with data.  If you are interested in empirical social sciences, I recommend you check him out at The Monkey Cage or at his blog, or one of his many excellent books.