I would also like to see the rates of those without a hs diploma. If you look at SPSS stats, it works out to resemble a bell curve. Those at the ends of the educational scale tend to be liberal, those in the middle tend to be conservative. Just look at inner cities for a visible example.
TYTT, it makes sense that the smartest people tend to be Libertarian. Those who actually take the time to think for themselves believe that people can and should think for themselves.