The rate falls in line with Romney's estimate August that he paid, "13.6 [percent] or something like that."
But that's only because the candidate decided to limit the deductions he and his wife took from their considerable charitable giving. Had the Romneys taken all of the deductions made available by their $4.02 million in 2011 donations, his effective tax rate could have been as low as 12.2 percent.
By not taking all the deductions, he paid an additional $265,500 to the federal government.
That decision contradicts a pledge Romney made during an interview in July, when he told ABC News he would not pay more in taxes "than are legally due and, frankly, if I had paid more than are legally due I don't think I'd be qualified to become president. I'd think people would want me to follow the law and pay only what the tax code requires."
Romney made a similar remark in January during a GOP primary debate, when he said, "I pay all the taxes that are legally required and not a dollar more. I don't think you want someone as the candidate for president who pays more taxes than he owes."
In the final accounting, Romney paid $1.9 million in taxes on $13.7 million in income for the year 2011.
The release of the financial information came just as Romney touched down for a campaign event in Nevada -- the home state of Senate Majority Leader Harry Reid, a Democrat who has been one of the most outspoken critics of Romney's handling of his tax returns.
Reid claimed in July that he had heard Romney didn't pay any taxes for the past 10 years, an accusation that prompted the Romney campaign to respond at the time that there was never a year Romney paid $0 in taxes. But the accusation still managed to perpetuate the pressure on the GOP candidate to release more financial information.
In a surprise move, the Romney campaign also released a written summary of 20 years of Romney's returns. Romney had previously pledged to release the two most recent years of returns and nothing else.
His 2011 return were posted in full this afternoon, as were health records for both Romney and running mate, Rep. Paul Ryan, R-Wis.
The release of Romney's full 2011 return and the 20 years of summaries came after months of hounding by Democrats for the tax returns. They called Romney's lack of openness about his tax records worrisome for a presidential contender.
Romney's tax saga has been going on since January, when, in a hastily arranged news conference after a dismal showing at a rally days before the South Carolina primary, he disclosed that his tax rate was "probably closer to the 15 percent rate."
At that time, Romney said it was traditional for nominees to release their returns in April -- "tax season," he added -- but the candidate backpedaled just days later, when, in an interview with Fox News' Chris Wallace, he announced he would, in fact, release the documents.
He told Wallace at the time that he'd "made a mistake ... holding off" as long as he had in releasing the returns.
So on Jan. 24, he took the plunge, releasing his 2010 returns and an estimate for the 2011 return, which wasn't ready yet, his campaign said.
His 2010 returns showed that Romney took in $21.7 million in income in 2010 and paid $3 million in taxes, or a little less than 14 percent.
The returns also showed that Romney gave $3 million in charitable donations in 2010, including $1.5 million to the Mormon church.
As calls intensified for Romney to release as many as 10 years of returns, the candidate continued to point to Sen. John McCain, R-Ariz., the 2008 Republican presidential nominee, as his role model on the issue. Romney noted that McCain only released two years of tax returns and maintained that he, Romney, had done everything "required of him by law" when it came to his financial documents.
But the criticism only continued when it emerged that Romney's campaign had requested "several years" of tax returns from those who were vetted as potential vice presidential candidates.
The focus on Romney's tax returns has long irritated Romney advisers, who believed the issue took Romney off message and dominated the news cycle when they would rather have focused on the economy.
For example, during a news conference in August that was intended to focus on his Medicare plan, Romney was hounded about his taxes and asked whether he'd kept a promise he made to ABC News, during an interview in Jerusalem, to "go back and look" and see if he'd ever paid a tax rate lower than 13 percent.
"I did go back and look at my taxes, and over the past 10 years I never paid less than 13 percent," Romney said at the time.
So why did Romney wait so long -- with Election Day so close -- to release his returns? The candidate and his wife told Parade magazine in August that one of the reasons they had hesitated to release their financial documents was the amount of money they give the Mormon church.
"Our church doesn't publish how much is given," Romney told the magazine. "One of the downsides of releasing one's financial information is that this is now all public, but we had never intended our contributions to be known. It's a very personal thing between ourselves and our commitment to our God and to our church."