Story highlights Bernie Sanders entered the 2016 race at a huge cash disadvantage

But he and Clinton are now about equal in fundraising

Washington (CNN) For Bernie Sanders, slow and steady wins the fundraising race.

The Vermont senator began his bid for the Democratic presidential nomination last year with a sizable financial disadvantage compared to front-runner Hillary Clinton. By the end of last June, Sanders had raised just shy of $14 million for his campaign, less than a third of the $47.5 million Clinton had raised for hers.

But the Sanders campaign slowly and steadily eroded the former secretary of state's fundraising advantage. Sanders slightly edged Clinton in contributions in 2015's fourth quarter, but his fundraising operation didn't kick into high gear until 2016. His campaign has outraised Clinton's every month this year by at least 50%. In March alone, "Bernie 2016" received $44.7 million in contributions, compared to $26.3 million for "Hillary for America."

Now, Sanders and Clinton are essentially even in total campaign contributions, with each campaign bringing in more than $180 million for their bids by the end of March.

With the primary campaign entering its final weeks, both campaigns are spending at a frenetic pace. The Clinton campaign spent in March more than it raised in contributions, with a so-called burn rate of 107%. Sanders had a burn rate of 99% for March. For the campaign to date, the Sanders campaign has spent 91% of the money it raised, compared to 84% for the Clinton campaign.

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