Ninety percent of registered voters say they have voted or plan to vote in November's midterm elections, according to a new American Barometer survey.

The poll, conducted by Hill.TV and the HarrisX polling company, found that 11.5 percent of voters said they had already voted in the elections, while 12.2 percent of respondents said they plan to vote in person before Election Day.

Another 48.7 percent of respondents said they planned to vote in person on Election Day, and 17.9 percent of voters said they planned to vote by mail or absentee ballot.

Ten percent of respondents said they did not plan to vote at all.

The poll comes amid a spike in voter enthusiasm among Republicans and Democrats in the final weeks before November's midterm elections, which are widely expected to be a referendum on President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE's first two years in office.

A Washington Post/ABC News poll released earlier this week found that 76 percent of voters said they are "absolutely certain to vote," up 11 points from those who said the same when asked during the 2014 midterms.

Millennial voters are also being watched closely in the run up to the midterms, with mounting speculation that youth turnout could be higher this midterm election year.

Seventeen percent of millennials polled said they planned to vote before Election Day compared to 11 percent of Gen Xers and eight percent of baby boomers who said the same, according to the American Barometer.

"Young people are the ones who say they are more likely to early vote in this poll and others, and less likely to vote on Election Day, so I wonder how that will affect youth voter turnout," Executive Features Editor at Morning Consult, Anna Yukhananov told Hill.TV's Krystal Ball on "What America's Thinking."

The American Barometer was conducted on October 13-14, 2018 among 1,000 registered voters. The sampling margin of error is plus or minus 3.1 percent.

— Julia Manchester