The rich tend to be lumped together as one economic group, as if people earning $250,000 a year (or even $1 million a year) are pretty much the same as those making $50 million.

But a new analysis of top incomes tells us that there is a big difference between the super-rich and the merely rich in how they earn money.

The paper , from Roberton Williams of the Tax Policy Center, compares two sets of 2009 IRS data. One group is American tax filers reporting income of $1 million or more. The other is for the 400 top earners in America, who made an average of $271 million each.

Americans with an adjusted gross income of $1 million or more make about a third of that from salaries and wages. Capital gains used to account for more than a third of their income, but since 2000 that share has fallen to 17 percent. Today, the largest share of their take comes from “other income” - mainly earnings from partnerships or S-corps, as well as other capital gains.

The “fortunate 400” – or top 400 earners – make much more of their income from capital gains and other income than from salaries and wages, which account for only 9 percent of their income. Capital gains as a share of their income has also fallen, from 72 percent in 2000 to 46 percent in 2009.

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