What do you conclude from that, and what do you conclude from studying, say, 1950, when the top federal income tax rate was over 90%?

My point in asking is this: quoting statistics such as the above is often a 'push poll' type situation, trying to suggest a particular conclusion, often by idealogues.

Interpreting that information requires a whole lot of other information and the conclusions to be drawn are not what one might initially assume.