Paying taxes is bad enough. Finding out you pay a larger percentage of your income than presidential candidate Mitt Romney or billionaire Warren Buffet makes it even worse.

But that's the case for millions of American, who pay higher rates because most or all of their income comes from a salary rather than dividends. The capital gains tax rate on investments currently tops out at 15%, while the highest rate for earned income is more than twice that at 35%.

As a result, it's typical for Buffet -- who has volunteered to pay more and publicly excoriated the government about tax equity -- to have a tax rate of around 17.4%, mainly on capital gains and dividends, while his now-famous secretary pays a higher rate.

That sore subject has been much in the political news lately, but now that it's tax season, it seems much more personal. But before you start throwing things at your computer or your accountant, look at the data. The wealthiest Americans may pay at lower rates, but they pay more in total taxes.

Here are some details about who pays how much in taxes.

Wealthier Americans pay higher taxes than middle- or low-income earners; according to the latest Internal Revenue Service data, Americans earning more than $1 million in 2009 paid at an average income tax rate of 25%, while the average rate for taxpayers earning $75,000 to $100,000 was 8%.

In contrast, Americans making $100,000 to $200,000 paid on average 12% in taxes -- but this group paid a quarter of all income taxes collected in 2009, according to IRS data. Add in those making up to $500,000 -- who paid at a rate of 19% -- and these two groups contributed 45% of all income taxes collected. Americans earning more than $1 million, on the other hand, in 2009 paid just 20% of total taxes collected.

The richest one-fifth of Americans accounted for 86% of all capital gains and dividend income last year, according to preliminary projections from the Tax Policy Center, a research group and think tank. About two-thirds of that went to the richest 1%, and 44% went to the top 0.1%.

According to IRS statistics from 2009, those who made $10 million or more grossed nearly $70 billion in long-term capital gains.

Both Romney and Buffett are paying their full tax bill due under the current tax code. As Diana Furchtgott-Roth, senior fellow at the conservative think tank Manhattan Institute, puts it, "If you think Romney should owe more, change the law."

Behind this political back-and-forth is a pressing need for the United States to raise revenue. The Congressional Budget Office recently projected a federal budget deficit of $1.1 trillion for fiscal year 2012, and spending cuts alone aren't likely to cover the difference. Just how to find new revenue, though, is controversial.

President Barack Obama has taken action to try to do just that. At his behest, Democrats in the Senate on Feb. 1 introduced legislation to enact the so-called "Buffett Rule," which would require anyone making more than $1 million to pay a tax rate of at least 30%.

Another frequent proposal is to raise the tax rate on capital gains. In a New York Times/CBS News poll released Jan. 24, slightly more than half of Americans agreed that income from capital gains or dividends should be taxed at the same rate as wages.

Still, many economists say the favorable rate on capital gains and dividends is vital to growth.

"Investors are supplying the capital that is needed to spur innovation," Furchtgott-Roth says. "They should be rewarded for the risk they are taking."

Critics disagree. "Capital gains is just one of the many ways the wealthy can lower their tax burden that is not available to most Americans," says Brad Borden, tax professor at Brooklyn Law School. "And it is usually at the expense of those in the middle class."

Indeed, a 2011 Congressional Research Service report argued that the capital gains tax has contributed to income inequality in recent decades as capital gains and dividends became a larger share of overall income -- and were much more unequally distributed. Borden suggests Congress allow the capital gains tax rate to rise to at least 20% by 2013, as currently scheduled.

Ending the preferential tax rate on capital gains alone won't eliminate the U.S. deficit, particularly given that nearly half of all Americans will not owe any income taxes at all for 2011, according to the Tax Policy Center.

In addition to longstanding itemized deductions, Congress during the last two years has substantially increased the Earned Income Tax Credit and established a host of new credits for childcare, education and retirement savings. In 2010, not only did 45% of taxpayers not owe income taxes, 90% of that group received government payments through refundable tax credits.

Important to note, the Tax Policy Center says, is that 60% of those who pay no income taxes earn less than $20,000, and 84% earn less than $100,000. Also, not paying income taxes does not preclude owing payroll taxes for Social Security and Medicare of up to 15.3%.

Still, about one-sixth of those not paying income tax in 2010 earned more than $100,000, and a handful escaped payroll tax as well, according to the Tax Policy Center. That's because those households received much of their income from tax-exempt bonds or from overseas sources for which they receive foreign tax credits. In exchange, they often accept lower interest rates from such bonds or they pay taxes to another country.

Some have proposed doing away with the U.S. system of complex tax credits and deductions and instead installing a flat tax or raising the marginal tax rate on all income brackets. Either step would require a full overhaul of the tax code -- and in the end, it may make little difference.

"Top earners will always find ways to shift their wealth into categories taxed at a lower rate," says Tax Policy Center's Roberton Williams. "Doubling the tax rate won't automatically double revenues."

A faster path to increased revenue would be for Congress to allow tax cuts enacted under the George W. Bush Administration to expire at the end of 2012. Continuing them, the Congressional Budget Office has said, would slash revenues by $5.4 trillion through 2022, forcing the Treasury to increase the national debt to cover the difference.

"The Bush tax cuts disproportionately benefit a small group of top-income earners," says Chuck Marr, director of federal tax policy at the Center on Budget and Policy Priorities. "And they are very expensive."

Ultimately, it is unclear whether any changes to the tax code can repair the widening gulf between the rich and the poor in the United States. Tax Foundation economist William McBride, for one, argues volatility in the stock market has had more impact on recent income inequality than taxes.

"The Bush-era tax cuts had provisions that benefited both high and low taxpayers," McBride says. "By contrast, inequality rose 12% between 1993 and 2000, following two tax rate increases on high-income earners."

Marr concurs. "Inequality is a pre-tax phenomenon," he says. "Going forward, we just have to decide how much we want to use taxes to fix it." (Editing by Jilian Mincer, Linda Stern and John Wallace)