Republican presidential candidate Mitt Romney released his long-promised 2011 tax return Friday, but the multimillionaire has resisted pressure to release many more years of tax forms that would provide insights into his sprawling finances.

Romney earned almost $13.7 million last year and paid more than $1.9 million in taxes _ an effective tax rate of 14.1 percent. In 2010, Romney paid about $3 million in federal income taxes _ or 13.9 percent.

By comparison, President Barack Obama's tax return shows he earned nearly $790,000 last year and paid an effective tax rate of almost 21 percent.

The tax release comes after a difficult week for Romney, in which a leaked, secretly recorded video showed him saying nearly half of the country doesn't pay income taxes, supports Obama and is dependent on government. "My job is not to worry about those people," Romney said in the video, released this week on the website of Mother Jones magazine.

He has spent much of the week trying to soften those remarks while facing criticism from some fellow Republicans over the workings of his campaign. The race for the election remains tight, but Obama holds a slight lead in recent polls and has pulled ahead in cash on hand for the crucial final campaign push.

Romney campaign officials said he and his wife, Ann, filed the tax return Friday with the Internal Revenue Service, after receiving an extension. Most Americans faced a tax filing deadline of April 17 this year.

Democrats have long tried to make an issue of what Romney pays in taxes and what he is willing to divulge about his investments, including overseas ones. Critics, including Obama, have urged Romney to follow his father's model. When George Romney ran for president in 1968, he set a precedent by releasing information on 12 years of tax returns.

Mitt Romney is refusing. He has said he is following the example of Republican Sen. John McCain, who released just two years' worth of returns in his race against Obama in 2008.

His campaign had promised to release his complete 2011 returns before the election Nov. 6. On Friday, Brad Malt, the trustee of the couple's blind trust, added that Romney and his wife last year claimed a deduction for $2.25 million of their $4.021 million in charitable contributions. In the previous year, a large percentage of those contributions went to the Mormon Church.

Several tax law experts said Friday that Romney's newly released tax returns would not be much help in uncovering the most persistent mysteries of his finances _ whether he used aggressive tax-deferral strategies, the specifics and tax advantages of his numerous offshore investments, the source of his massive retirement account and the details behind his now-closed $3 million Swiss bank account.

The analysts said those details could emerge only if Romney provided far more of his tax returns _ including files dating back to his years at Bain Capital, the private equity firm he cofounded and then left in 2001.

"The issue has never been Romney's 2011 tax return _ in fact, it is a distraction to the real issues," said Edward D. Kleinbard, a law professor at the University of Southern California and former chief of staff of Congress' Joint Committee on Taxation. "All the important compliance and policy questions relating to Romney's personal tax matters relate to the past."

Joseph Bankman, a Stanford University law school professor and expert on tax law, said Friday, "It's the Bain years we'd really need to know to have a full assessment of his tax strategies."

The vast majority of Romney's income has come from investments, which are taxed at a lower rate than wages. His wealth has been estimated as high as $250 million, and much of it is held in a blind trust. Campaign aides have stressed that Romney makes no decisions on how his money is invested.

On average, the wealthy in the U.S. pay higher income tax rates than those who make less. People making $1 million or more annually paid an average effective rate of 25 percent last year in federal income and payroll taxes, according to the nonpartisan Tax Policy Center.

The White House has argued that even so, some millionaires pay lower rates than many of those earning less. That is largely because many wealthy people earn income from dividends that are taxed at just 15 percent, instead of the top 35 percent rate on salaries.

As the struggling economy remains the top issue for voters, Romney has seized on cutting taxes as a possible solution. He proposes dropping all income tax rates by 20 percent, reducing the top tax rate from 35 percent to 28 percent. He says he would pay for the rate cuts by eliminating or reducing tax credits, deductions and exemptions, but he won't say which ones would go.

Romney's tax release quickly overshadowed Friday's other events, as both campaigns reached out to the country's older voters. Obama's campaign released a new video, based on the leaked Romney remarks, arguing that the Republican candidate derides seniors behind closed doors.

Americans 50 and over, including the large and vocal Baby Boomer generation, are especially important because they register in greater numbers and are almost twice as likely to cast their ballot as younger voters. An Associated Press-GfK poll released this week found Romney was favored by seniors likely to vote, 52 percent to 41 percent for Obama.

Seniors also make up about 22 percent of those not paying income taxes, as they get tax breaks that offset their income.

Both campaigns made pitches at the national convention of the largest interest group for seniors Friday.

Polling shows Obama with a slight lead nationally, as well as in many of the eight or so battleground states that will decide the election. The president is not elected by popular national vote but in state-by-state contests.

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Associated Press writers Nedra Pickler, Mark S. Smith and Julie Pace contributed to this report.