More than half of Minnesotans have contributed to candidates or other political causes, according to a new Star Tribune Minnesota Poll.

Only 45 percent of likely voters say they have never given money to a political candidate, party or political action committee. A full 54 percent said they had contributed. The poll found that Minnesotans of nearly all demographic stripes claimed they had given money to political causes at least once.

The poll, conducted Sept. 8-10, interviewed 800 likely voters. It has a margin of sampling error of plus or minus 3.5 percentage points.

Its findings shed new light on regular Minnesotans' political giving patterns, which often go unnoticed because low-dollar donors' names need not be publicly disclosed. It shows that far more people contribute, or claim to have contributed, than was previously known.

The poll found that women were more likely than men to say they had given to political campaigns, and Democrats were more likely than Republicans or independents to contribute.

"I belong to the teachers' union, so I don't directly give money to certain candidates, but my union does," said Deb Myhre, a 43-year-old special education teacher from Columbia Heights and a Democrat. "The candidates they support are the candidates I support."

Conservative Republican blogger Gary Gross said he has given political cash as well.

"I've contributed to a couple Republican candidates and also once to the county Republican Party, but it's very infrequent," said Gross, 58, of St. Cloud.

According to the poll, 58 percent of women said they have ponied up cash for politics, compared with 50 percent of men. Fifty-nine percent of Democrats said they have given at least once, compared with 53 percent of Republicans and 48 percent of independents.

The poll found that outstate Minnesotans are slightly more likely to have contributed than those in the metro area, and that 65 percent of Minnesotans over age 65 had contributed at least once.

Those who spend many of their waking hours soliciting political cash professed shock that more than half of all Minnesotans say they have given.

"I would have expected the number to be much lower than that. That surprises me," said Ken Martin, the DFL Party chair. "If every one of those people did contribute, we wouldn't have to fund-raise anymore."

Republican Party Chairman Keith Downey was similarly surprised. But, he said, the cash may flow to campaigns that the State Capitol fundraisers never see.

"Individuals support people that they know and like in their local communities all the time, so I guess when you think over your entire lifetime … those numbers do make sense," Downey said.

That's why Gross has contributed. "I knew two of the candidates I contributed to, longtime friends, and I thought they were good, viable policymakers," he said.

The polling results run counter to recent trends showing that state campaigns are becoming increasingly dependent on a few big-money donors rather than grass-roots fundraising.

A recent Star Tribune analysis found that for Minnesota House candidates, people who gave less than $200 were on the decline.

In 2008, more than 85 percent of House candidates' campaign donations came from those low-dollar donors. By 2012, that figure had dropped to just over two-thirds.

But this year's figures appear to show a resurgence in low-dollar contributions. Much of that credit may go to a unique state program that has encouraged low-dollar donations over the years. The Political Contribution Refund allows people to donate up to $50 to a candidate or party and get a full tax refund from the state.

In some past years, when the governor's office has been on the ballot, more than 40,000 Minnesota taxpayers contributed to political campaigns through the refund program.

Another Minnesota program allows taxpayers to check a box on their tax returns to contribute to a general fund that subsidizes candidates' fundraising. Checking that box does not lessen taxpayers' refunds.

Both programs encourage Minnesotans to take part in political fundraising.

In addition, candidates constantly barrage voters with come-ons to contribute. In a typical week, a politically active Minnesotan will receive dozens of e-mails from politicians asking for cash.

Not all those appeals are successful.

"We call these people permission-based spammers," said Eric Raymond, a 53-year-old poll respondent from Chanhassen. Raymond, a vice president at an ad agency, said he is libertarian or conservative on issues. Although his e-mail inbox is often filled with political fundraising appeals, he never gives. "It's easier just to delete it rather than to unsubscribe."

Staff writer Abby Simons contributed to this report.

Rachel E. Stassen-Berger • Twitter: @rachelsb