Hillary Clinton leads Bernie Sanders by 22 points in Iowa, according to a new poll.

A Monmouth University survey released on Tuesday found Clinton with 55 percent support compared with Sanders's 33 percent. That’s in line with the RealClearPolitics average of Iowa polls, which shows Clinton with a 24.7-point lead over Sanders.

Martin O’Malley takes 6 percent in the Monmouth survey.

Female voters, who favor Clinton over Sanders 61 percent to 27 percent, are bolstering her in the state. Among men, Clinton holds a narrow lead, 47 percent to 42 percent.

While Sanders has a 10-point lead over Clinton among younger voters, she dominates among voters over the age of 50, taking 63 percent support compared with 27 percent for Sanders.

And Clinton’s support comes from those who are more likely to participate in the caucuses on Feb. 1, the poll found.

Among those who have participated in past caucuses, Clinton’s lead expands to 27 points.

Sanders does better among independents in the state who say they plan to caucus with Democrats in February; he and Clinton each take 45 percent support among this bloc, which makes up about 14 percent of those sampled.

“The core of this electorate is going to be registered Democrats. And Clinton appears to have that group firmly in her corner,” Monmouth polling director Patrick Murray said.

Furthermore, with only 54 days until voters cast their ballots in the Hawkeye State, there appears to be little room for Sanders to make inroads.

Forty-one percent of those surveyed said they have made up their minds, and 38 percent said they have a “strong preference” for one of the candidates but remain open to persuasion. Only 11 percent said they have a “slight preference” in the race, and 10 percent said they’re undecided.

Clinton’s lead in Iowa is down from its high point over the summer, but she has consistently outpaced Sanders even as he has attracted crowds of thousands on the campaign trail and cut into her poll numbers elsewhere.

Sanders’s best chance to win an early primary contest appears to be in New Hampshire, where he and Clinton are essentially tied in the polls.

The Monmouth University poll of 405 likely Democratic caucusgoers in Iowa was conducted Dec. 3–6 and has a 4.9 percentage point margin of error.