When Warren Buffett pointed out that the American tax system was so egregiously rigged that he paid a smaller share of his income in taxes than his secretary, very few of his peers chimed in. It was so quiet that one might have thought Mr. Buffett’s case was a fluke. It wasn’t.

The Congressional Research Service found that 200,000 millionaires — almost two-thirds of taxpayers with taxable income above $1 million — paid a lower tax rate (combining income and payroll taxes) than the typical taxpayer making less than $100,000.

This is mostly because the rich make a huge chunk of their income from stocks and other investments, in the form of capital gains and dividends. Those are not subject to payroll taxes and are taxed at 15 percent, lower than the 25 percent marginal rate paid by a family earning wages of $100,000 a year.

Many wealthy people — and their Capitol Hill defenders — argue that the comparison is unfair because dividends and capital gains are also subject to taxes when corporations pay taxes on profits. Yet even taking corporate taxes into account, and excluding itemized and other deductions, the Congressional Research Service found that 94,500 millionaires paid a lower share of their income in taxes than 10.4 million taxpayers making less than $100,000 a year.