It's tax day at the White House and both President Obama and Vice President Biden have filed their tax returns.

Tax returns released by the White House show Obama and his wife, Michelle, together made $2.7 million last year.

While that is far more than the U.S. median household income of about $50,000, it is also far less than the Obamas made the previous year. In 2007, they made $4.2 million.

Nearly all of their earnings last year came from the president's two best-sellers. The nonfiction books -- "Dreams From My Father" and "The Audacity of Hope" -- brought the Obamas nearly $2.5 million in royalties.

The Obamas paid $855,323 in federal income tax and donated $172,050 to 37 different charities. The largest donations in 2008 were to CARE and the United Negro College Fund for $25,000.

Biden reports that he and his wife earned $269,256 last year.

The couple's main sources of income were salaries from the Senate, Widener University, Delaware Technical & Community College and royalties from the audio rights to the vice president's memoir, "Promises to Keep."

According to tax returns released by the vice president's office, the Bidens paid $46,952 in federal income taxes and $11,164 in Delaware state income taxes. They donated $1,885 to charity. 

But the White House points out that number is not the final sum of their charitable contributions. The release says the Biden's donate to their church and contribute to their favorite causes with time.

A financial disclosure form Biden filed a year ago as a senator valued the Bidens' assets at between $59,000 and $443,000.

April 15 is the deadline to file U.S. tax returns.

FOX News Eve Zibel and The Associated Press contributed to this report.