Ron Paul continues to rake in cash at a healthy clip.

The GOP presidential contender raised $13 million from October through December, national campaign chairman Jesse Benton confirmed. The figure was first reported this morning by Politico.

Paul's take includes a haul of more than $4 million from a mid-December "money bomb," the quick-hit, online fundraising bursts that he first deployed in the 2008 campaign.

The Texas congressman also continues to lead the GOP field -- and President Obama -- in donations from members of the armed forces. An analysis from the non-partisan Center for Responsive Politics shows Paul has so far received more than $95,000 from donors who list their occupations as one of the military branches or Department of Defense. It's a trend Paul has noted often on the campaign trail, including in his speech to supporters after his third-place finish at the Iowa caucuses.

Campaign finance reports for the end of 2011 aren't due to the Federal Election Commission until later this month.

Rick Santorum has enjoyed some fundraising success since he started surging in Iowa, and told an audience on Monday that he had raised more in the past few days than he had in several months. He reportedly raised $1 million in just one night after his second-place Iowa finish.

Before the Iowa caucuses, Newt Gingrich's campaign said he raised about $9 million in the fourth quarter.

Overall, Mitt Romney has raised the most campaign cash among the GOP candidates followed by Rick Perry, according to a chart on the Center for Responsive Politics' website. The Texas governor's fundraising has been widely reported to be way down since he started plummeting in the polls.