SACRAMENTO (CN) — Boosted by an infusion of Latino voters in Southern California and a new voting system in five counties, California’s primary turnout recorded a sharp increase this month.

While counties are still counting the last batches of provisional ballots, the secretary of state’s latest update pegs the June 5 primary turnout at 34 percent, up from just 25 percent participation in the June 2014 primary.

Experts say the semi-official results suggest that the state’s largest demographic group turned out in droves in Southern California.

Researchers at UCLA’s Latino Policy & Politics Initiative estimate that while primary turnout increased countywide in Los Angeles, participation in majority-Latino districts skyrocketed compared to 2014.

“In 66 percent of the Latino precincts, there was an estimated 50 percent increase in the number of ballots cast, compared to a 20.8 percent in the non-Latino precincts,” according to the UCLA voting analysis.

Researchers examined more than 3,600 voting precincts in L.A. County, home to the most registered voters of any of California’s 58 counties, and focused on the approximately 325 precincts where Latinos make up over 75 percent of registered voters. The study compared Latino precinct results to the other 1,765 “non-Latino” precincts, where Latinos make up less than 25 percent of the voting base.

According to the analysis, only 2 percent of Latino precincts saw a decrease in votes cast, while 28 percent of non-Latino districts saw a decline.

The trend spread to nearby Orange County, where a companion UCLA demographics study also found increased voter turnout in heavily Latino districts. The two counties account for nearly 30 percent of the 6.4 million votes counted statewide as of Monday night.

The rush to the polls in Southern California may have been influenced by the increased number of Latino candidates running for statewide office. The Orange County analysis found the recent primary featured a 500 percent increase in the number of Latino major-party candidates compared to June 2014.

Five Latino politicians advanced in statewide races and will appear on the November ballot. Latinos will be in runoffs for attorney general, lieutenant governor, U.S. Senate, insurance commissioner and secretary of state.

One notable Latino candidate who will not be on the November ballot is Antonio Villaraigosa. The former L.A. mayor won only his home county in his gubernatorial bid, finishing third to Gavin Newsom and John Cox statewide.

Eric McGhee, a researcher at the nonpartisan Public Policy Institute of California who specializes in the state’s political geography, expects final statewide voter participation to be on the “high side of normal.” McGhee said California traditionally has strong primary turnout compared to other states.

“There are states where primary turnout is around 6 percent; it can be pretty bad,” McGhee said. “So California is historically pretty good.”

Republican strategist and author Tony Quinn said voters were intrigued by the gubernatorial and high-profile congressional races.

“It was a higher turnout than we had expected,” Quinn said. “There was more interest in this governor’s race and that ultimately led to more people voting.”

A new voting system piloted in five counties may have also boosted turnout.

Sacramento, Nevada, Napa, Madera, and San Mateo counties mailed ballots to every registered voter. The counties replaced traditional neighborhood voting stations with regional centers where voters simply walked in and dropped off their completed ballot. Voters could also send their ballot through the mail up to Election Day.

The mail-in method was approved in 2016 by lawmakers trying to jumpstart voter interest after the dismal 2014 turnout.

Average turnout in the five counties was 40 percent, including 36 percent in Sacramento and 31 percent in San Mateo, the largest of the five.

San Francisco had the best showing of any major county, with turnout exceeding 52 percent. Los Angeles County recorded 24 percent; San Diego County 38 percent.

County elections officials have counted more than 6.4 million ballots and are expected to have all votes counted by July 6.