When state officials last week said that 128,000 voters had switched to the Republican Party in just the last three months, experts dubbed the unexpected surge the "Trump effect."

Now, they have another term for it: "Clerical error."

That's what Pennsylvania's Department of State officials said Monday when they released a statement correcting the number of Pennsylvania voters who have switched their party affiliation before the April 26 primary.

And they weren't off by only a few.

On March 28, state officials released a registration database reporting that nearly 215,000 Pennsylvania voters had switched their party affiliation to either Democratic or Republican since the start of 2016.

One week later, they corrected that number to just over 104,000 voters during that same Jan. 1 to March 28 period - a nearly 52 percent decrease.

State officials on Monday attributed the drop to a "clerical error" - one made by a Department of State contractor who had edited and updated the database manually.

"This has to do with inadequate capabilities of our database, which cannot be generated automatically," said Kaitlin Murphy, deputy press secretary at the Pennsylvania Department of State. "There was a human error."

Murphy said the change came after a realization during the weekend that some of the March 28 data released last week had included figures from 2015.

"As soon as we learned that was the case, we took immediate action, reviewed all current and historical data sets, and the numbers have now been corrected," said Secretary of State Pedro A. Cortés in a statement Monday.

All numbers are now accurate, the spokeswoman said, and voters should encounter no difficulties at the polls later this month.

But where do the party gains stand?

Pennsylvania's GOP has welcomed just over 63,000 Democrats, independents, and third-party voters to the party between Jan. 1 and March 28 - a hefty 50 percent drop from the nearly 128,000 reported last week.

On the Democratic side, the party added about 41,000 Republicans, third-party, and independent voters who switched affiliation during that same period. That's also a drop from the 86,500 the state reported last week.

And as for independents and third-party voters, about 8,300 switched their affiliations away from the major parties. Last week, the state had said that figure was nearly four times as large.

The state did not provide new data on how many first-time registrants each party gained.

"It's a lot closer between the Rs and the Ds than it was before," said G. Terry Madonna, the veteran pollster who directs the Center for Politics and Public Affairs at Franklin and Marshall College. Last week, he said, the March 28 data revealed an unprecedented number of party switches.

On Monday, Madonna said there are "still a large number of people switching" compared with previous years such as 2014, when only 28,000 voters each switched to the Democratic and Republican Parties. (The state does not have comparable figures for the last presidential year).

"But it's not as significant as we once thought," he said.

As for the Trump effect?

Whether people are switching their party registration to support Trump or vote against him, Madonna said his effect still lingers. (And the much-closer registration numbers on the Democratic side indicate the race between Hillary Clinton and Bernie Sanders is only intensifying, too, he said.)

"It doesn't change the reason people are switching," he said. "It just changes the intensity of it."