Gingrich has vowed to continue campaigning through the GOP convention even if he loses the pivotal Florida primary Tuesday, a proposition that becomes increasingly expensive as more and more geographically dispersed states vote.

The former House Speaker's numbers still trail both Ron Paul — who raised $13 million over the same period — and Mitt Romney, who brought in $24 million between October and December. Rick Santorum has not yet announced his fundraising totals.

The effect of Romney's financial advantage has been obvious in Florida, where The Washington Post estimates Romney more than doubled Gingrich's spending on commercials and campaign efforts. While Gingrich has been aided by multimillion-dollar donations to his associated super-PAC from casino mogul Sheldon Adelson, that amount has been more than matched by Romney supporters giving to groups supporting his campaign.