President Barack Obama

WASHINGTON - President Barack Obama and his wife, Michelle, reported adjusted gross income of $789,674 in 2011 and paid just more than 20 percent of it to the federal government in taxes.

Their income declined nearly $1 million from the previous year, when the president was reaping larger amounts from sales of his best-selling books. The numbers were disclosed in the Obamas' federal income tax return and gift-tax return, released Friday by the White House, along with those of Vice President Joe Biden.

Barack and Michelle Obama paid $162,074 in income taxes, an effective tax rate of 20.5 percent. In a statement, the White House suggested that Barack Obama believed that he should pay a higher rate, noting that his administration wants to reform the tax code and ask "the wealthiest Americans to pay their fair share while protecting families making under $250,000." Biden and his wife, Jill, reported adjusted gross income of $379,035 and paid $87,900 in federal tax, an effective tax rate of 23 percent. That is roughly the same as what the couple reported last year.

The annual release of tax returns by Barack Obama and Joe Biden was more politically charged than in previous years, with the Obama campaign assaulting the likely Republican presidential nominee, Mitt Romney, for his refusal to disclose more on his taxes.

The Obama campaign also has drawn attention to the even lower tax rates paid by Romney and his wife, Ann, who derive much of their income from interest on investments, which are taxed at a lower rate than wage income.

Mitt Romney's campaign declined to say when the candidate would release his personal tax returns, noting that he has already provided an estimate for 2011.

In January, Romney estimated that he had earned $20.9 million in 2011 and paid about $3.2 million in taxes, for an effective tax rate of about 15.4 percent.

"Gov. Romney has already released his 2010 return and an estimate of his 2011 income and taxes," Andrea Saul, a campaign spokeswoman said. "He will release his full 2011 return when it is filed."

That could be early next week, although in the past Romney has filed extensions for his tax returns, so it's possible the campaign may not release the full return until later.

Obama still earned about half his total income from sales of his books in 2011, the White House said in a statement. But that is sharply lower than in 2010, when the Obamas reported adjusted gross income of $1,728,096 and paid $453,770 in federal taxes - an effective tax rate of just more than 26 percent.

The Obamas also reported donating $172,130 - or about 22 percent of their adjusted gross income - to 39 charities. Their largest donation was a $117,130 contribution to the Fisher House Foundation. Barack Obama is donating the after-tax proceeds from his children's book to Fisher House, a scholarship fund for children of fallen and disabled soldiers.