After making $659,637 in 2007, Santorum made over $920,000 each of the last three years, topping out at $1.1 million in 2010.
Santorum still has a modest income compared to his rival, frontrunner Mitt Romney, but somewhat surprisingly contributed under 2% of their total income to charity.
The GOP candidate earned most of his money from "consulting," which is common of politicians after they've left office. Santorum, Gingrich and Romney have all earned hefty consulting fees in their time away from office.
Politico was the first to report Santorum's tax returns, and you can read them for yourself here.