Since the Bush tax cuts “the rich” have been paying a larger share of the federal tax pie, but that pie has been shrinking as more wealth flees the country, more of the wealthy expatriate, more jobs leave the country, and more people drop out of the workforce.

[Editor’s Note – The raw CBO report can be found HERE]

Wall Street Journal:

President Barack Obama says someone has to pay more taxes if the U.S. is to tame its budget deficit and provide the government he thinks the nation needs. He proposes that the best-off Americans pay more. It’s only fair, he says.

“There are a lot of wealthy, successful Americans who agree with me because they want to give something back,” he said in a speech in Roanoke, Va., that set off dueling campaign ads. “Look, if you’ve been successful, you didn’t get there on your own.”

His Republican opponent, Mitt Romney, counters that the deficit can be reduced without raising taxes if Washington is tough on spending. He thinks raising taxes on the best-off would be unwise and unfair. “President Obama attacks success, and therefore under President Obama we have less success,” he said.

The contrasting comments underscore philosophical differences over the roles of the individual and society. But the most tangible disagreement is on taxing the rich.

“Who’s right: Obama or Romney? Both. Or neither,” says Joseph Thorndike, a tax historian. “When it comes to taxing the rich, there is no single, objectively correct answer. You can talk all you want about asking rich people to pay ‘their fair’ share,’ but don’t kid yourself. You’re just trying to turn private opinions into public policy.”

“I’m struck” he adds, “how the facts can be used selectively by either side.”

Academic tomes have been written about revamping the tax code so it finances the government while doing less damage to economic growth. But, countless congressional hearings later, the U.S. is no closer to a consensus on “fair share” than when the income tax was born 100 years ago.

The top marginal income-tax rate, the most visible metric, has gone from 7% in 1913 to 92% in the 1950s to 28% with the Tax Reform Act of 1986 to 39.6% in the Clinton years to today’s 35%. Mr. Obama wants to raise that; Mr. Romney wants to cut it while eliminating loopholes and deductions to make up the lost revenue.

Over the past three decades, Americans—including most of the rich—have paid less of their incomes to Washington. Top earners have received more of the income and paid more of the taxes; a growing number at the bottom have paid less or, in some cases, nothing.

Whether that is fair is a question of politics and values. Facts can inform the debate. Here are a few salient ones:

The top 5%, top 1% and top 0.1% of Americans have been getting a bigger slice of all the income and paying a growing share of federal taxes.

To measure the tax burden over time, Congressional Budget Office economists look beyond income-tax returns. They add federal income, payroll, excise and corporate taxes and calculate them as a percentage of income, broadly defined to include wages plus the value of government- and employer-provided benefits.

From Ronald Reagan to Barack Obama, the tax code has been tweaked and the economy has had its ups and downs, and the share of federal taxes paid by the top 5% and the top 1% has risen faster than their share of income:

In the 1980s, the top 5% averaged 22.6% of income and paid 28.5% of taxes.

In the 1990s, the top 5% averaged 25.3% of income and paid 34.3% of taxes

In the 2000s, the top 5% averaged 28.4% of the income and paid 40.3% of the taxes.

That doesn’t mean that the best-off are living on less. The top 1% averaged income of $1,530,773 this year (up $174,083 from 2004, when the data series begins) and paid federal taxes of all sorts of $422,915 (up $20,704 from 2004), according to estimates by the Tax Policy Center, a number-crunching joint venture of the Brookings Institution and Urban Institute.

Average tax rates have come down for everyone. On average, the tax bite on the rich is bigger—except for those whose income mainly comes from capital gains and dividends.

Across the earnings spectrum, Americans’ share of income that went to taxes fell in the 1980s, rose in the 1990s and fell again in the 2000s. This year, taxes and other receipts will cover only two-thirds of federal spending; the government will borrow the rest.

For those in the top 1%, whose incomes are more volatile than others, the average tax bite in 2007 was 28.9%, below the 1995 Clinton-era peak (35.3%) but higher than the 1986 Reagan-era trough (24.6%.)

Most Americans, though, have seen the share of their income that goes to taxes fall steadily. For earners in the middle, the tax bite eased from 18.9% in 1979 to 16.6% in 1999 to 14% in 2007 even before the recession and recession-fighting tax cuts.

The rich do, on average, pay more of their income in taxes than the middle class. So do the super-rich—on average.

The annual Internal Revenue Service scorecard of the top 400 taxpayers—who reported average incomes of $200 million—showed they paid 19.9% of their adjusted gross income in federal income taxes in 2009, well above the rate paid by the middle class. Those with incomes between $100,000 and $200,000, for instance, paid about 12%. (The IRS tally for the top 400 counts only income reported on tax returns, and only income taxes. Neither the IRS nor CBO calculates figures for the 1% using the broader definitions of income and taxes.)

The fortunate 400, though, paid a lower rate than the not-quite-so-rich, those with incomes over $1.5 million. The main reason: More than 60% of the top 400’s income was from dividends or capital gains in 2009, and those are taxed at a top rate of 15%, lower than many pay on wages.

The share of taxes paid by the bottom 40% of the population has been shrinking along with their share of income.

In 2007, the bottom 40% received 14.9% of the income (including the value of government benefits) and paid 5.9% of all federal taxes. In 1979, they had a bigger share (17.4%) of the income and paid more (9.5%) of the taxes.