TUCSON — Early voting has become increasingly popular in the past several Arizona elections, and state and county officials expect at least half of the state’s voters to cast ballots early for this year’s presidential election.

Early voting starts Oct. 2.

Each of Arizona’s 15 counties handles the early voting program, including signing voters up on a Permanent Early Voter List that the Legislature approved last year.

“I have every reason to believe that at least 50 percent of the Arizona voters, given recent elections, are likely to be voting early,” Deputy Secretary of State Kevin Tyne said.

Karen Osborne, elections director in Maricopa County, the state’s most populous, said 610,000 early ballots had been requested as of Sept. 15.

The county has 1.6 million registered voters, and the number of requests for early ballots has increased every year since 1991, when early voting as opposed to absentee balloting began, she said.

Many voters find early balloting easy and attractive.

“There is no line at your mailbox,” Osborne said. “It gives you extra time to look at the issues, and if you have an issue that you’re not real familiar with, you can talk to others and make that decision in the comfort of your own home.”

Osborne said her office is prepared for an 80 to 85 percent turnout. “We’ve been gearing up for this for a long time,” she said. “The energy this time lends itself to a lot of participating.”

Maria Weeg, executive director of the state Democratic Party, said party officials are seeing “tremendous interest” in early balloting.

And Republican Party spokeswoman Camilla Strongin said the ability to sign up for automatic permanent voting by mail is likely to change the dynamic — as is Sen. John McCain’s campaign, in trying to get those favoring his presidential candidacy to vote early.

“That kind of falls in line with the differences of having a presidential election where the candidate is actually from your home state,” she said.