SALEM — Before Bernie Sanders halted his presidential campaign, he might have caused a surge in Oregon voters who switched to being Democrats for the state’s May primary election.

New statistics released by the Secretary of State’s Office show the Democratic Party is Oregon’s first political party to top 1 million voters.

“These numbers are for the record books, and demonstrate the strength of our party’s vision for all Oregonians and the work of Democratic activists from all corners of the state,” Carla “K.C.” Hanson, chair of the Oregon Democratic Party, said Tuesday in a statement.

But Kevin Hoar, the communications director for the Oregon Republican Party, said it’s not surprising that the crowded Democratic presidential field had initially increased interest on the Democratic side of the May 19 primary election.

“At this point, for the Democrats, this is their moment to celebrate because we think it’s all downhill from here,” Hoar said, adding that Republicans are focusing their voter registration efforts toward the Nov. 3 general election.

Both the Oregon Democratic and Republican parties restrict voting in their primaries to members of their party. Veteran political scientist Jim Moore said it appears that many previously unaffiliated voters changed their registration to Democrat, likely to vote for Sanders, which helped put the Democratic party over the 1 million mark.

“It shows that there is an electorate out there that’s paying attention to politics and will take actions in order to vote as they want to in the primary,” said Moore, a professor at Pacific University.

The lineups for the May 19 primary ballot were set weeks ago. The Democratic presidential candidates are Sanders, Elizabeth Warren, who had ended her campaign before Sanders, and Joe Biden, the presumptive nominee. President Donald Trump is the sole Republican candidate.

As of April, Oregon had 2,862,831 registered voters. By party, they included:

• Democrats, 1,006,266

• Republicans, 711,344

• Independent, 123,189

• Libertarian, 19,215

• Working Families, 9,128

• Pacific Green, 7,679

• Constitution, 3,682

• other parties, 17,660

But the second-largest group of voters, behind Democrats, comprises the 962,453 voters who chose no party.

Moore said the new data do not represent significant change in the Oregon electorate. The number of unaffiliated voters has been rising for decades at the expense of the major parties.

That shift took off in the 1990s but began in the 1970s in the aftermath of the Watergate scandal and President Richard Nixon’s resignation, according to Moore. Instead of seeing political parties as a way to accomplish common goals, voters came to view both major parties as corrupt.

Oregon’s system of automatic “motor voter” registration through the DMV has swelled voter rolls in recent years, especially for unaffiliated voters. Overall registration in Oregon is up 2.85 % from a year ago. That could mean a large turnout at the November general election, which is open to all voters regardless of party.

“It looks like we’re going to have the possibility once again, as we did in 2018, of a record number of people voting but the percentage of registered voters will be lower simply because there are so many more voters,” Moore said.

The state party also announced it was forgoing its customary in-person nominating convention and instead would use mail and online voting to choose its delegates to the Democratic National Convention, which now is scheduled for mid-August in Milwaukee, Wisconsin. The results of the May primary election will determine how 61 of Oregon’s delegates are apportioned among the three candidates.

Oregon also has 13 automatic delegates who are elected officials or party officers.

The Republican National Convention will be held in late August in Charlotte, North Carolina.