BURLINGTON, Vt. – Bernie Sanders’ presidential campaign raised more than $33 million in the final three months of last year in a way that rewrote the record books for White House campaigns. The tally for the year-end quarter pushed his total raised last year to $73 million from more than 1 million individuals who made a record 2.5 million donations.

“This people-powered campaign is revolutionizing American politics,” said Jeff Weaver, Sanders’ campaign manager. “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 2,513,665 donations to Sanders’ campaign broke the record set four years ago by President Barack Obama’s re-election committee. Through Dec. 31, 2011, Obama had chalked up 2,209,636 donations.

The more than 1 million donors to Sanders also is a milestone unmatched by any first-time White House candidate. Obama’s millionth donor in his 2008 campaign came on Feb. 27 of that election year. (In the next election cycle, the incumbent president’s re-election campaign hit the 1-million- donors mark on Oct. 17, 2011.)

Unlike other campaigns, small contributions made up the vast majority of all the money Sanders’ campaign raised. The average donation to Sanders during the past three months was $27.16.

Unlike other presidential campaigns, 99.9 percent of Sanders’ supporters may give again because they have not reached the legal limit on donations to traditional campaign committees. Only a few hundred of the more than 1 million Sanders donors have given the maximum $2,700.

Unlike candidates who have coordinated with so-called super PACs, Sanders has refused to work with the fund-raising behemoths that have corrupted American politics.

All told, Sanders supporters gave $33,281,952 during the Federal Election Commission reporting period that ended at midnight on New Year’s Eve. Secretary Clinton’s campaign announced on Friday that she raised $37 million in the last quarter for use in the Democratic primary. The total for Sanders far surpassed donations in either of the previous two quarters of his eight-month long campaign and brought the fundraising total for 2015 to $72.8 million. Sanders ended the year with $28.4 million cash on hand.

The record number of donations to Sanders is one way to measure the grassroots enthusiasm for his campaign. Another sign of his success has been big turnouts at rallies and town meetings in Iowa and New Hampshire and other states. In Iowa alone, more than 35,000 have come to Sanders-sponsored campaign events.

“Bernie is the only candidate generating the kind of broad-based enthusiasm and excitement that Democrats must have in order to raise funds for a general election campaign and keep the White House and make gains in Congress,” Weaver said.