My previous post, in one chart:
(Click here for larger size).
Bubbles to the right are more democratic countries, measured using the Unified Democracy Scores; bubbles to the left are more autocratic countries. Note how the left side of the graph has much more volatility, even within single countries, as expected; the bubbles move up and down like crazy. By contrast, on the right side of the graph everything oscillates more sedately. (Try following Lebanon, for example; you can also zoom in to particular regions of the graph). For another interesting view, change the color to "regime type" and set the Y axis to plot GDP per capita (rather than GDP per capita growth). (Change the scale to "log," too, for a clearer view).
(Data on economic growth from the Penn World Table.)