Tax the Rich ... even more?

I found this graph, and thought it did a great job of explaining the current tax situation in the US; as you can see, the top 5% earn 35% of income and pay about 60% of income taxes.

My question is, what is a 'fair' tax rate?

In 1981, the top 5% only paid 35% of all income taxes ... so over the last 28 years (of which the White House was controlled by Republicans for 20 years), the share of income taxes paid by the top 5% has increased 70%!