More than 60,000 Democrats are abandoning their party, switching to the Republican Party ahead of this year’s primary election in Pennsylvania.

Reporter Lisa Mascaro of the Tribune news service called it “the most sizable shifts of partisan allegiance ever in Pennsylvania.”

61,500 Democrats have become Republicans so far this year, part of a 145,000 jump in Republican registrations since the fall 2015 election, according to state figures analyzed by both parties. It’s more new Republicans than in the previous four years combined.

GOP frontrunner Donald Trump is predicted to benefit from the shift on Tuesday when Pennsylvania voters head to the polls.

“The party-switching has been going on in an evolutionary way for two decades. This just propelled it faster,” said Franklin and Marshall University professor G. Terry Madonna. “Many of them are Reagan Democrats – white, working-class, blue-collar, incomes of $35,000 to $40,000 or less, high school educations or less.”

“They feel frustrated, they feel left behind,” Madonna added. “They feel Trump is sticking it to the man.”

Some of the voters that switched said they are fed up with the Democrat Party’s political correctness and that the party no longer speaks for them.

Eight million voters live in Pennsylvania. “Democrats still hold a more than 900,000-voter advantage over the Republicans in Pennsylvania,” Mascaro reports.