Slightly more than half of Americans polled now believe further investigation into President Donald Trump, public censure, or impeachment proceedings should begin, up sharply from one month ago, a new poll found.

About 52% of Americans want to see one of the following: begin impeachment proceedings (22%), continue to investigate potential political wrongdoing by the president (25%), or publicly censure him (5%), according to a survey of 944 adults conducted between May 31 and June 4 by NPR/PBS NewsHour/Marist Poll. Of the 944 respondents, 783 were registered voters with a margin of error of plus or minus 5%, and 339 were Democrats or Democratic-leaning independents with a margin of error of plus or minus 7.6%.

Adults over the age of 18 and residing within the contiguous U.S. were contacted on cellular phones or landlines, and after validation of age, personal ownership, and non-business use of the mobile phone, an interview was conducted in English by live interviewers.

About 39% of respondents said no further investigation or action was necessary, which is largely reflective of President Trump’s approval rating, currently pegged at 41%. Trump’s approval rating has never been higher than 43%, in February 2019 when unemployment dipped below 4%, or lower than 35%, following the racial violence in the wake of an August 2017 white supremacist rally in Charlottesville, Virginia.

What may be most notable about the new poll is only one month ago, before Special Prosecutor Robert Mueller spoke publicly regarding his two-year investigation into election interference by Russian operatives, those favoring impeachment amounted to 16%. The new poll shows roughly a 28% increase among those who believe impeachment should be pursued. The poll has a margin of error of plus or minus 4.5%.

The growth in support for impeachment comes from a near-doubling of independents who say they want impeachment over publicly censuring the president or taking no further action, NPR reported.

In what direction future polls will move depends largely on what information is uncovered or released. In May 1973 when the Watergate hearings began, a Gallup poll found only 19% favored the impeachment of former President Richard M. Nixon. However, some 15 months later, in August 1974, after edited transcripts of Nixon’s Oval Office tapes were released under a Supreme Court order, 57% were in favor of removing him from office.

While support for impeachment remains relatively low, the poll did have some good news for Trump: fewer voters said they will “definitely vote against” him in the 2020 election. In January, 59% polled indicated they would not vote for Trump’s re-election while the poll completed this week showed that number dropped to 51%.

When compared with the 2016 election in which 54% of Americans did not vote for Trump, the current number appears to indicate an uptick in his electability. Some of this positive showing may be due to 84% of Democrats and Democratic-leaning independents indicating they have not made up their mind as to the Democratic candidate they will support.