Hillary and Bill Clinton paid $3.2 million in federal income tax last year, a rate of 34.2 percent. Their 2015 return was released today by the Clinton campaign, almost five months after they signed it for filing.

The Clintons overpaid the Treasury and got a refund of more than $1 million.

The couple's income plunged last year. Adjusted gross income for 2015 was $10.6 million, compared to $27.9 million for the previous year. Charitable contributions accounted for 9.8 percent of their adjusted gross income.

Clinton is releasing the returns for two reasons: transparency and the opportunity to bash Donald Trump. The Republican nominee has refused to make his 2015 tax data public.

"Donald Trump is hiding behind fake excuses and backtracking on his previous promises," said Jennifer Palmieri, communications director for the Clinton campaign.

Trump and his lawyer have said the IRS is auditing his returns, so he can't or won't release them, although there is no legal prohibition on releasing returns that are being audited.

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