Fraud is rare. Suspicion isn't. EPA/MICHAEL REYNOLDS

Nearly half of Americans say that voter fraud occurs at least somewhat often according to a new Washington Post-ABC News poll, a viewpoint at odds with studies showing it rarely occurs in U.S. elections.

The poll also finds 63 percent of voters are confident that votes in this year’s presidential election will be counted accurately, down from about 7 in 10 in 2004.

Republicans and Donald Trump supporters express the greatest concern about voter fraud and election accuracy -- worries which the GOP nominee has stoked on the campaign trail. The dynamic marks a reversal from 2004, when Democrats were more doubtful about the legitimacy of the vote.

The Post-ABC poll finds 46 percent of registered voters say voter fraud -- described as multiple votes being cast by a single person, or an ineligible person casting a ballot -- occurs very or somewhat often, while 50 percent say it occurs occasionally or rarely. Over two-thirds of Trump voters say voter fraud occurs often, compared with less than one-third of Clinton supporters. Whatever the partisan differences, at least one-fifth of every major demographic and political group says voter fraud occurs somewhat or very often.

The prevalence of voter fraud appears to be widely overestimated. A 2012 investigation by the News21 investigative reporting project published in The Washington Post found only 2,068 cases of alleged voter fraud had been reported since 2000, including only 10 cases of voter impersonation over the entire period. A separate study by Loyola Law School professor Justen Levitt found 241 potentially fraudulent ballots over a 14-year period out of 1 billion ballots cast.

The Post-ABC poll also finds a sizable gap in skepticism of vote counting accuracy between Clinton and Trump supporters. Just under half of Trump supporters (49 percent) say they are “not too” or “not at all” confident” votes will be counted accurately, while just 18 percent of Clinton supporters are similarly skeptical.

That's a reverse in skepticism from 2004 when supporters of Democrat John Kerry were far more likely to think votes would not be counted properly than backers of Republican George W. Bush -- then, 44 percent of Kerry supporters and just 14 percent of Bush supporters were not confident that votes would be accurately counted.

Democrats skepticism of votes being counted accurately is likely due to the contested outcome of the 2000 presidential election, when the U.S. Supreme Court ordered manual vote recount in Florida, resulting in George W. Bush winning the state and the presidency. Trump supporters' heightened concerned about the vote count is likely fueled by the candidate's own statements. Last month, Trump warned that the election might be "rigged" against him, saying "we may have people vote 10 times."

What may matter most heading into the fall is how seriously people perceive the voting process as it occurs, and whether candidates raise questions about its legitimacy that amplify concerns that exist today. Skepticism can linger even if all goes smoothly, as in 2004 when Bush won by a significant margin and Kerry conceded quickly. A Post-ABC poll one month after the election found 49 percent of Kerry's supporters saying they were not confident the vote was counted accurately, hardly changed from the final days before Election Day.

The Post-ABC poll was conducted September 5-8 among a random national sample of 1,002 adults reached on cellular and landline phones. The margin of sampling error is plus or minus 3.5 percentage points for overall results; the error margin is four points among the sample of 842 registered voters.