I have been digging on this, and the picture I posted is misleading. I found it somewhere on the internet, but it looks like Nancy P used it before and it is very misleading, earning a "Pants on Fire" rating from Politifact.
Here it is, so I stand corrected.
http://www.politifact.com/truth-o-meter/...t-debt-accumul/Using the corrected figures does mean that, superficially at least, Democrats have a point. The debt did still increase more, on a percentage basis, under Bush than it did under Obama. But other problems with the chart and its methodology undercut even this conclusion.