Two-thirds of voters say presumptive GOP presidential nominee Donald Trump Donald John TrumpUS reimposes UN sanctions on Iran amid increasing tensions Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally MORE should release his tax returns, a new poll finds.

According to the Morning Consult survey released Tuesday, 67 percent of registered voters overall — and 60 percent of Republicans — said presidential candidates should release their tax returns.

ADVERTISEMENT

Only 21 percent of respondents said they don't think candidates should have to release their tax returns.

Trump's campaign has said his tax returns are not an issue that matters to voters.

“This is an issue the media is interested in. This isn’t an issue that middle America is interested in,” Trump aide Paul Manafort said earlier this month.

Democratic presidential front-runner Hillary Clinton Hillary Diane Rodham ClintonJeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Momentum growing among Republicans for Supreme Court vote before Election Day Warning signs flash for Lindsey Graham in South Carolina MORE has slammed Trump for not yet releasing his returns. She said over the weekend that his refusal to release the returns could suggest Trump "pays no federal income tax."

Other people, such as 2012 GOP presidential nominee Mitt Romney, have also criticized Trump for not releasing his returns.

The Morning Consult poll found that 75 percent of respondents think presidential candidates should be required to release their birth certificates, and 55 percent think candidates should release their medical history.

It also showed Clinton with a slight lead over Trump in a general election match-up, 38 to 35 percent. Libertarian candidate Gary Johnson garnered 10 percent support, and 17 percent of respondents said they were undecided.

The poll was conducted among 2,001 registered voters May 19–23. The margin of error is 2 percentage points.