Democrats are better for the economy than Republicans

Slate has a new infographic that compares U.S. economic performance metrics under Democratic and Republican presidents from 1957 to 2007. On almost every measure, Democrats are ahead. This follows up on a New York Times piece from a few weeks ago that came to similar conclusions, including that income inequality tends to decrease under Democratic presidents:

It is well known that income inequality in the United States has been on the rise for about 30 years now … Over the entire 60-year period [from 1948 to 2007], income inequality trended substantially upward under Republican presidents but slightly downward under Democrats, thus accounting for the widening income gaps over all.