Bernie Sanders, the Vermont senator vying for the Democratic presidential nomination, raised $33 million over the final three months of 2015, according to his campaign staff. That was enough for Sanders to come within $4 million of the amount raised by Hillary Clinton, front-runner for the Democratic nomination.

Funds collected over the fourth quarter of last year helped Sanders collected a total of $73 million since he announced his candidacy. Clinton, a former senator and secretary of state, raised $37 million October through December and a total of $112 million since launching her primary campaign, according to ABC News.

“This people-powered campaign is revolutionizing American politics,” Jeff Weaver, Sanders' campaign manager, said in a statement Saturday. “What we are showing is that we can run a strong, national campaign without a super PAC and without depending on millionaires and billionaires for their support. We are making history, and we are proud of it.”

The campaign currently has $28.4 million left over from the $73 million raised, according to the statement.

Sanders raised nearly as much as Clinton in the final quarter of 2015 despite a very different approach. The Sanders campaign has sought to woo a deep network of low-dollar donors and has accepted more than 2.5 million online donations.

Clinton, on the other hand, has relied primarily on high ticket prices to fundraisers to bankroll her campaign. Over 760 of Clinton's donors listed their occupation as CEO or another form of chief executive, according to figures obtained by CNBC in October. The average CEO donated $2,300.

The average Sanders donation was $27, and just a few hundred donors have pledged $2,700, the maximum figure allowed.

Republican candidate Donald Trump used the Sanders announcement as another opportunity to claim he is funding his own campaign, despite financial filings showing the opposite.