For the second time in four days, a new poll of the U.S. Senate race in Maine shows Democratic challenger Sara Gideon with a 5 percentage-point advantage over Republican Susan Collins.

A poll of 500 likely voters released Monday by Suffolk University had 46 percent of respondents favoring Gideon, while 41 percent said they preferred Collins. The poll also showed 5.4 percent of voters were undecided, 3.8 percent said they would vote for Green Independent candidate Lisa Savage and 1.6 percent said they planned to vote for Republican-turned-independent Max Linn.

The survey, conducted in collaboration with the Boston Globe, was completed between Sept. 17-20 and had a margin of error of plus or minus 4.4 percentage points.

Voters were asked about their ranked-choice preferences as well, but only 31 of 500 people surveyed answered the question. Of those, 15 ranked Gideon second, while six people said Collins was their second choice.

Gideon, Maine’s Speaker of the House, has maintained a consistent lead in public polling since July. Last week, a New York Times/Siena University survey of 663 likely voters also showed Gideon with a 5 percentage-point advantage, 49-44 percent. That poll did not include Savage or Linn, nor did it ask about ranked-choice voting.

Another poll last week, from Quinnipiac University, put Gideon ahead of Collins by 12 points, although that appears to be an outlier at this stage. A Quinnipiac poll from July showed the Democrat with a 47-43 percent advantage and a survey conducted by Colby College in late July put Gideon ahead 44-39 percent, with 12 percent undecided and 6 percent saying they planned to support another candidate.

As has been the case with other polls, Collins, the four-term incumbent, struggled with women in the Suffolk University/Boston Globe poll. Just 33 percent of women polled favored the Republican, compared with 54 percent for Gideon. Collins does lead among men, 49 percent to 38 percent.

The poll found Vice President Joe Biden has a commanding lead over President Trump among Maine voters – 51 percent of those surveyed favored the Democratic nominee, while 39 percent plan to vote for the president, with 7 percent undecided. Other polls have shown similar leads for Biden in Maine, a state Democrat Hillary Clinton won in 2016 by 3 percentage points.

Trump won Maine’s 2nd Congressional District four years ago, securing one electoral vote in the process, something he hopes to do again this time around. Among voters in the 2nd District only, the Suffolk poll showed Biden with a 47-45 percent edge.