Add this to the list of Democratic worries ahead of the midterms: Younger voters — a cornerstone of the party’s electoral coalition — make up a smaller share of early and absentee voters so far than they did in 2020.

More than 15 million voters have already cast their midterm ballots, according to the United States Elections Project. But young voters have contributed to a smaller fraction of that turnout compared to this time two years ago, according to interviews and a POLITICO analysis of voter data.

The party has had high hopes that younger voters motivated by the Supreme Court’s scuttling of abortion rights and President Joe Biden’s cancellation of some student debt would turn out in force — and help them to defy losses that the party in power typically suffers in midterm elections. They could still show up to the polls on Election Day. But their disappearance from the ranks of early voters so far puts Democrats at a disadvantage, because the party still has to chase their votes instead of banking them ahead of Nov. 8.

In North Carolina, which has a close U.S. Senate race and a set of state legislative races that could determine whether abortion remains legal in the state, the median age of voters who cast ballots through Oct. 26 was 66, according to state data. Voters aged 30 and younger account for just 5.4 percent of ballots cast so far, compared to 16.5 percent of those who voted early or absentee in 2020. Republicans’ share of the early vote is also slightly higher now than it was at the same time two years ago.

The overall situation looks better for Democrats in Pennsylvania, where they have maintained a more than 50-point advantage in absentee ballots returned so far, a similar share to 2020. But that is still despite low participation there from young voters, who the party still needs to turn out in order to win the state’s U.S. Senate seat.

“Democrats are going to need younger voters to come out on Election Day in order for the numbers to hold,” said Tom Bonier, CEO of TargetSmart, a Democratic data firm.

Early voting data is not a crystal ball for the coming election: Operatives from both parties and political analysts are quick to note that shifting voter habits after the Covid-19 pandemic, changing laws and former President Donald Trump’s repeated attempts to sow doubt about mail voting also make it hard to establish a solid early voting baseline.

Claudia Cedillos, left, waves signs with her daughter Montserrat before a campaign rally for Democratic then-presidential candidate Joe Biden, on Nov. 2, 2020, in Miami, Fla.