Enlarge By Alex Brandon, AP Vice presidential candidate Joe Biden, left, the Democratic senator from Delaware, earned a little over $300,000 last year, tax records show. Here, Biden is seen with Democratic presidential candidate Barack Obama, the senator from Illinois, greeting supporters in Battle Creek, Mich., on Aug. 31. BIDEN'S TAX RECORDS BIDEN'S TAX RECORDS Total income Tax paid Charitable donations Biden $319,853 $66,273 $995 Source: USA TODAY research CREATE A SCENARIO FOR 2008 CREATE A SCENARIO FOR 2008 USA TODAY's interactive electoral vote tracker lets you build election scenarios, share them with friends and study past election outcomes. 2007 TAX RETURN DETAILS 2007 TAX RETURN DETAILS WASHINGTON  Democratic vice presidential candidate Joe Biden and his wife gave an average of $369 a year to charity during the past decade, his tax records show. Democratic presidential nominee Barack Obama's campaign today released 10 years' worth of tax returns for Biden, a senator from Delaware, and his wife Jill, a community college instructor. The Bidens reported earning $319,853 last year, including $71,000 in royalties for his memoir, Promises to Keep: On Life and Politics. LOOK BACK: McCain, Obama financial records The Bidens reported giving $995 in charitable donations last year — about 0.3% of their income and the highest amount in the past decade. The low was $120 in 1999, about 0.1% of yearly income. Over the decade, the Bidens reported a total of $3,690 in charitable donations, or 0.2% of their income. Biden spokesman David Wade said in an e-mail that the Bidens "also contribute to their favorite causes with their time as well as their checkbooks." Wade said Jill Biden has volunteered to help military families and the family "pitched in driving supplies to the Gulf Coast after Hurricane Katrina." Nationally, more than two-thirds of U.S. households reported giving to charity in 2004, with average contributions of $2,047 that year, according to a study released in January by the Center on Philanthropy at Indiana University. Those households who gave to charity averaged donations of about 3% of their income, says Patrick Rooney, the center's interim executive director. Another study of wealthy households in 2005 found average yearly donations of $40,746 from people with incomes from $200,000 per year to $500,000 per year, Rooney says. But like most statistics on giving, those numbers are skewed upwards by a small number of people who give large amounts to charity, says Rooney, formerly the center's research director. Other vice presidents have been criticized over their charitable contributions. Then-Vice President Al Gore came under fire when his 1997 tax return showed only $353 in donations to charity; he and his wife, Tipper, gave $15,000 to charity, or nearly 7% of their income, in each of the following two years. When Vice President Dick Cheney was campaigning in 2000, he defended his family's charitable donations of $209,832, or about 1%, of the $20.6 million he earned from 1989 to 1999. "It's a private matter … a matter of private choice," Cheney said in 2000. Last year, Cheney and his wife, Lynne Cheney, donated more than $166,000 to charity, or about 5.5% of their income, according to the Chronicle of Philanthropy. Obama and his wife, Michelle, released tax returns earlier this year showing they earned more than $4.2 million last year, about $4 million of it from sales of Obama's two books, Dreams from My Father and The Audacity of Hope. The Obamas gave more than $240,000 to charity last year, about 5.7% of their income, their tax return shows. Their charitable giving has risen with their income; in 2000, when the couple made $240,726, they gave $2,350 to charity, about 1% of their income. Republican presidential nominee John McCain reported income of $405,409 last year. His wife, Cindy McCain, the head of a Phoenix beer distributorship, files separate tax returns. McCain's campaign released only a summary of one of Cindy McCain's tax returns, showing she earned more than $6 million in 2006. John McCain reported giving more than $202,000 — a quarter of his income — to charity in 2006 and 2007, the only years for which his campaign released his tax returns. His campaign didn't release information about his wife's charitable contributions, however. In 2006, her total itemized tax deductions, a category which includes charitable contributions and other deductible items such as mortgage interest, was $569,737, or 9.3% of her income. The McCain campaign has not said when his running mate, Alaska Gov. Sarah Palin, will release her tax returns. The Democratic National Committee has criticized McCain for only releasing two years' worth of his returns, rather than the seven years' worth of complete returns released by Obama and the decade's worth from Biden. Compared with the two presidential candidates, Biden's income is much more modest. His earnings in the past decade ranged from a high of more than $320,000 in 2005 to a low of $210,797 in 1999. Besides his Senate salary and his wife's earnings, Biden also reported earning $20,500 a year from Widener University, where he's listed as an part-time, adjunct instructor of a constitutional law class. Widener has campuses in Delaware and Pennsylvania. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. 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