Mitt Romney and his wife, Ann, paid $1.94 million in federal taxes on last year's income of $13.7 million, for an effective tax rate of 14.1 percent, his campaign said Friday.

That's slightly above the 13.9 percent rate the couple paid in 2010. Most of the 2011 income was from investments.

Campaign officials said the couple filed the return Friday with the Internal Revenue Service, after receiving an extension. They were to publicly release their full 2011 returns late Friday.

Romney's taxes have emerged as a key issue during the 2012 presidential race with President Barack Obama. Romney released his 2010 tax returns and a 2011 estimate in January, but he has declined to disclose his returns from earlier years.

His vast fortune and his long association with Bain Capital, the private equity firm he cofounded, have been much discussed this year.

His campaign earlier estimated that Romney would pay about $3.2 million in taxes for the year, an estimate well above the $1.9 million actually paid. He paid about $3 million in federal income taxes in 2010 — an effective rate of 13.9 percent.

Critics, including Obama, have urged Romney to release more than just the two years of returns and follow his father's model. When George Romney ran for president, he released 12 years of tax returns.

Mitt Romney's campaign did put out a summary Friday by Brad Malt, the trustee of the couple's blind trust, saying that over the 20-year 1990-2009 period, the Romneys owed both state and federal income taxes and paid federal taxes at an effective annual rate of 20.2 percent

Obama's own tax return for last year showed that he and his wife, Michelle, paid $162,074 in federal taxes on $789,674 in adjusted gross income, an effective tax rate of 20.5 percent. Their income plunged from $1.7 million in 2010, with declining sales of the president's books. In 2009, the Obamas reported income of $5.5 million, fueled by the best-selling books.

The Romneys' exact totals for 2011 were federal taxes of $1,935,708 and on income of $13,696.951.