SACRAMENTO, Calif. >> Nearly 2.6 million ballots are still to be counted in California’s presidential primary election, California’s Secretary of State Alex Padilla said Thursday.

With the 6 million ballots already counted, that would put turnout at 8.6 million, or 48 percent, if all the ballots are certified.

Although the outstanding ballots are unlikely to swing presumptive Democratic nominee Hillary Clinton’s win in the nation’s most populous state, down-ballot elections could be affected as counting continues.

“The final, final turnout numbers and percentage won’t be known for several days,” Padilla said at a post-election forum in Sacramento. “But overall we do know that turnout is above the 2012 levels. Maybe not quite 2008 levels, but it was good.”

Mindy Romero, director of the California Civic Engagement Project at UC Davis, said the numbers released Thursday indicate more voters participated than were anticipated in the days leading up the election.

“It means that you got more of the people that don’t typically vote,” Romero said, adding that, absent detailed data, “we would expect we got more young people to turn out.”

The respected Field Poll had forecast turnout of 8 million, or 44.7 percent of the state’s 17.9 million registered voters, before Tuesday’s election.

The 48 percent turnout indicated Thursday fell in-between California’s 31.1 percent turnout in the 2012 primary and the historic 57.7 percent of the 2008 primary.

“Still, that is a good year and I think that is something to feel good about,” Romero said.

The survey of unprocessed ballots at all 58 county elections offices included 616,000 outstanding ballots in the most populous county, Los Angeles.

Voter turnout is unlikely to have matched a record number of registrations for a variety of reasons, experts who study turnout said.

Donald Trump secured the Republican nomination a month before California’s primary. An Associated Press delegate count the day before the primary showed Hillary Clinton had clinched the Democratic nomination. Nonpartisan voters may have been ill-informed or confused about how to vote in the presidential race.

“For no-party-preference voters, it was honestly quite a challenge,” Padilla said.

Mitchell and Romero said the AP report likely did not have a major effect on turnout because the majority of California votes were mailed in before the news.

Padilla said it’s hard to quantify.

“It’s so hard to measure, it’s all anecdotal,” Padilla said. “It did, it didn’t, it motivated some people to turn out with extra vigor, versus it discouraged somebody else.”

The Field Poll forecast that as many as 5 million voters would cast mail-in ballots, which had to be mailed by the June 7 primary. California law allows vote-by-mail ballots postmarked by election day and received at clerks’ offices within 3 days to be counted.

“We don’t know how many ballots were postmarked on or before election day that are in the process of arriving, still in the window to be processed and counted and added to the tally,” Padilla said.

Clinton has nearly 2 million California votes to 1.5 million for Bernie Sanders so far. In the Republican primary, Trump has 1.2 million votes, or 75 percent.