(CNN) A new poll suggests that a race for president between Donald Trump and Hillary Clinton could yield the lowest support for a Republican candidate among young voters in decades.

The survey, conducted by the Harvard University Institute of Politics , finds that in a hypothetical matchup, 61% of likely voters age 18-29 say they would vote for Clinton, while just 25% would vote for Trump. That's worse than most other recent Republican candidates for president.

Since 1992, exit polls have found Republican candidates average 38% support among voters under 30. Sen. John McCain notched 32% against Barack Obama in 2008, marking the low-point for GOP candidates dating back to 1972, when modern exit polling began. Ronald Reagan was the only Republican candidate to win the under-30 vote since then.

As this year's campaign for president has rolled on, younger Americans have tilted more Democratic generally, according to the IOP's surveys. Last fall, 36% said they considered themselves Democrats, that's up to 40% in the new survey. Republican affiliation has held about even at 22%, while the share who are independent has dipped from 40% to 36%.

Before asking about the current crop of candidates, the survey asked young Americans if they would prefer a Democrat or a Republican win the next election. The share saying they'd like a Democrat to win has climbed from 55% last spring to 61% now, while the percentage who favored a Republican dipped from 40% to 33%.

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