"People of class drink alcohol" - with charts which start at zero
img340.imageshack.us
img340.imageshack.us
I think this shows the distribution more clearly, however, I still don't think that any of the demographic categories listed maps to "class".
[1] http://news.ycombinator.com/item?id=1313745 http://blogs.discovermagazine.com/gnxp/2010/05/people-of-cla...
Though FWIW, I don't take much stock in the ability of most IQ tests to measure intelligence, since it seems a bit silly to put it on a single dimensional scale.