SANTA ANA (CBSLA) – In what could be a sign of a major demographic shift in the region, Orange County now has slightly more registered Democrats than Republicans, according to new numbers released Wednesday.

O.C. has 547,458 registered Democrats, compared to 547,369 registered Republicans in data provided by the O.C. Registrar of Voters, a margin of 89 voters.

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A whopping 440,711 voters had no political affiliation, making up about 27 percent of the electorate. While 43,884 voters registered with the American Independent Party.

The last time the Democrats had a majority in the county was in 1978 – and it was by a margin of 15 voters, according to Neal Kelly with the Registrar’s office.

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Experts say immigration and demographic changes have tipped the scales.

“We have more immigrants, it’s much more ethnically, racially-diverse, and we do have more college-educated voters,” Sarah A. Hill, associate professor of political science at Cal State Fullerton, told CBS2 Wednesday. “And all of those demographic groups are going to trend Democratic.”

Last November, Democrats swept all four congressional seats in O.C., a longtime Republican stronghold. In the 45th congressional district, Rep. Katie Porter, pulled off a surprising win over two-term incumbent Republican Rep. Mimi Walters. In the 48th District, 15-time incumbent Rep. Dana Rohrabacher lost to real estate executive Harley Rouda. In the 49th District, Democrat Mike Levin captured the U.S. House seat held for years by retiring Republican Rep. Darrell Issa.

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Hillary Clinton won the county by eight points in the 2016 election, the first time a Democratic presidential candidate had won the district since Franklin D. Roosevelt did it 1936, according to the L.A. Times.