As of Monday, a record nine million have registered to vote in Pennsylvania.By Jon Delano

PITTSBURGH (KDKA) — Monday was the last day to register to vote in Pennsylvania. But while a record number of Pennsylvanians have registered, millions across the nation have not.

Pennsylvania’s voting-age population is just under 10.2 million people. As of Monday, a record nine million have registered to vote. But that still leaves over a million citizens who didn’t register, and, of course, many registered voters will skip this election, too.

“It could be cynicism. I’ve heard too much. It could be a lack of information. Could be they’re too busy. Could be they don’t know how,” says Quinnipiac pollster Tim Malloy.

Malloy says this is despite an expectation that voter turnout will jump from 139 million voters in 2016 to over 150 million voters this year.

“Sixty percent of the people vote – maybe that’s about it. That means 40 percent don’t,” Malloy told KDKA political editor Jon Delano on Monday.

Reasons for not voting are many, even with on-line voter registration, says Duquesne University professor Kristen Coopie.

“You have to provide a lot of information. You have to have a license or some sort of ID number for the state to verify your identity. For some people, the process of registering is complicated enough,” said Coopie.

And then there’s all the moving around that Americans do these days.

“If you’ve moved, if you’ve gone off to college, if you’re a college student, if you’ve changed addresses, you might not take the time to update your registration,” she notes.

Some don’t vote in protest, too. Coopie also says those least likely to vote are still the young, less educated, lower-income people, and racial minorities.

“Generally, higher income, older, more educated voters, typically Caucasian voters, are more likely to participate,” she adds.

But most experts think this year could be different as record voter turnout could change everything.