Late on Monday, Mitt Romney released his 2010 tax returns, showing that he paid 13.9 percent of his income in federal taxes. (His rate is relatively low because most of his money comes from investment income, which is taxed at a lower rate than wages.) But how does Romney stack up to previous presidential candidates? Here’s a chart for comparison:

Sources, caveats, details: I tried to use candidates’ tax returns two years before the election to compare with Romney’s, although that wasn’t always possible.

Candidate Obama appears to have had the highest tax rate of those in the sample. In 2006, Barack Obama’s income was $991,296 and he paid $277,431 in taxes, or 27.9 percent. (He made considerably more in 2007, thanks to book royalties, and paid $1.4 million in taxes on $4.2 million in income, for an even higher tax rate of 33.3 percent.)

In 2006, John McCain had $358,414 in income and paid 33.8 percent of that in taxes. His wife Cindy, who filed separately, raked in $6.06 million, and together they paid about $1.7 million in taxes for a combined rate of 26.5 percent.

John Kerry’s overall rate is so low — lower than Romney’s, in fact — because his return is getting lumped together with that of his (wealthy) wife, Teresa Heinz, who had a lot of investment income. On his own, Kerry paid 22.9 percent in federal taxes in 2003 on his $395,338 salary, which included Senate income plus the sale of a 17th-century Dutch painting. Heinz, for her part, had an income of $5.07 million and paid $628,401 in federal taxes, or 12.3 percent. Here’s a fuller rundown by The New York Times.

George W. Bush’s 1998 tax return is here (PDF) — he reported $18.5 million in income, which included $17 million in carried interest from the Texas Rangers baseball deal, and paid $3.8 million in taxes, or 20.55 percent.

Bob and Elizabeth Dole’s 1994 tax returns were written up by the Los Angeles Times. They pulled in $596,908 in income and paid $155,756 in taxes, or 26 percent, but that was much higher than they’d paid in previous years. As the Times reported, “Over the period of 1987-1993, the Doles paid a minimum of 10.7% of their earnings in federal income tax, and a maximum of 19%.”

Bill Clinton’s 1990 tax return is described here. The Clintons took in $268,646 that year and paid $50,932, or 18.9 percent.

Michael Dukakis’s 1987 return is described here. The Dukakises took in $108,957 in income and paid $25,892 in taxes, 23.7 percent.

Update: This post was updated to list all income figures and to alter the chart to reflect the combined rate paid by the McCains (originally I’d just had what John McCain paid alone).

Related: The Post annotates Romney’s tax returns, and my colleague explained why Romney’s taxes were so low.