[jeromec]

You're right about the data being normalized, so it doesn't matter how many millionaires there are, and the top 1% is still the top 1%. However, that top 1% can be a richer 1%. Take this from the article:

In the late 1970s, the top 1 percent took home 9 percent of total national income. Now the top 1 percent’s take is more than 20 percent.

The chart you referenced shows tax revenues on the top 1% roughly doubled for the time period from 1979 to 2007, but over that approximate time period so did the total percent of the national income going to the top 1%! That would appear to explain much, if not all, of the increase right there. One wouldn't be able to take home double the income yet pay the same in taxes without serious loopholes.