Rick Santorum released four years of tax returns Wednesday night, more years than any of the other Republican presidential candidates.

The forms, dating back to 2007, show that the former Pennsylvania Senator steadily increased his income in years after he left government.

In 2007, Santorum, who listed his occupation as consultant, earned $659,637 and paid $167,759 in taxes.

Santorum earned more than $1.1 million in 2009, and gave away $29,822 in charitable contributions that year.

In 2010, Santorum, who filed jointly with his wife, listed an adjusted gross income of $923,411 and the couple paid $264,284 in taxes, a rate of 28.6 percent, more than double what Mitt Romney paid on $21 million in income.

The returns were first reported by Politico.