For more than 160,000 ­Minnesota voters, Election Day has come and gone.

In record numbers for a midterm election, Minnesotans are using absentee ballot and mail voting to cement their choices well before most polls open. During the past week alone, absentee ballots have been flooding in at the rate of 10,000 per day.

A Star Tribune analysis shows that those voting absentee tend to be older and are regular voters. About 70 percent of this year’s absentee voters cast ballots in 2006, 2008, 2010 and 2012. Another 17 percent voted in at least three of those elections. Only a sliver of those voters consistently used absentee ballots in the past.

“These are people who tend to vote both in midterms and in general elections,” said Tom Erickson, deputy campaign manager for Republican Mike McFadden’s U.S. Senate campaign. “These are people that are not independents. They tend to be Republicans or Democrats.”

They also tend to be older. More than half of all early ­voters are over 65, according to the Star Tribune’s analysis of absentee ballots accepted so far. Just in the last week, younger voters have started flooding election offices.

The Star Tribune also found that, by Minnesota House district, Democratic and Republican strongholds have each contributed a little less than 40 percent of the already counted votes. Voters in swing districts have posted about 20 percent.

That may be as parties wanted. Both Republicans and Democrats have emphasized finding their partisans who tend to vote in presidential elections but not in midterm elections when the governor is on the ­ballot. For that population, the ease of voting from home at any time may be extra appealing.

An easing of absentee voting restrictions that took effect this year, coupled with the parties’ redoubled efforts to push early voting, has led to a surge that could provide an unexpected margin for some candidates.

As of midweek, the last numbers reported by the secretary of state’s office, 125,348 absentee ballots had been accepted. That’s compared with 77,677 such ballots that had been cast by this time in 2010, the last midterm election.

And the rush of absentee ballots that arrive between now and Election Day can be substantial. In 2010, an additional 49,000 absentee ballots came in the final days.

For partisans the change has been a boon, allowing campaigns to specifically target individual voters to get their absentee ballots returned. They then can drop them from their lists and concentrate on other prospective voters.

The push for early voting also means candidates and parties are frontloading their campaigns more than ever. Typically get-out-the-vote efforts have not begun until mid-October.

This time, said DFL Chairman Ken Martin, “We started ours on Sept. 19.”

As part of that effort, Democrats brought in high-profile visitors, including First Lady Michelle Obama, Vice President Joe Biden and both former President Bill Clinton and former Secretary of State Hillary Clinton, to the state weeks ago.

Both Martin and GOP Party Chairman Keith Downey have received regular updates since mid-September on who has already voted and whether they are more likely to be Democrats, Republicans or something else. Both party chairs, who use proprietary lists identifying voters by party, claim at least a slight edge in the early voting population so far.

“It’s safe to say that both parties are driving a lot of voting in this early voting window. It appears that voters are responding,” Downey said.

The surge

According to a Star Tribune analysis, many counties have already accepted as many absentee ballots as they processed in all of 2010. Minneapolis and St. Paul, the state’s two biggest cities, have already exceeded their 2010 numbers.

In 2013, a DFL-controlled Legislature and DFL Gov. Mark Dayton changed the state’s law to allow absentee voting without having to give a reason. Previously, voters had to legally swear they were disabled, ill, out of the precinct, serving as an election judge or had a religious observance in order to obtain an absentee ballot.

“We’re busy, but we’re not overwhelmed,” said Cindy Reichert, Anoka County’s election manager, taking a break from calling would-be absentee ballot voters who did not properly fill out their paperwork.

“It is a labor intensive process,” she said of the work in her county. “A lot of hands touch each ballot.”

Sam Cari, a GOP-leaning Deephaven attorney, joined the wave of absentee ballot voters in Hennepin County. He voted absentee for the first time this year. “It is relatively straightforward,” said Cari, 28.

When he voted about a month ago, Cari said he considered the possibility that something might happen that would change his picks. But he said nothing has.

Democratic voter Tasha Foss was similarly certain.

“I am sure how I feel about the people I vote for,” said Foss, 31, of Maple Grove, who works at the union-supported ­Laborers’ Training Center.

A critical advantage

Getting those drop-off voters out, Martin said, could make a difference of one to two percentage points — a critical advantage in close races.

“There are a number of legislative races around the state that are on the knife’s edge right now,” Martin said. “One to 2 percent could make the difference between winning and losing.”

Downey said it may take weeks to figure out if the ­party’s push on early voting made a difference.

“It’s an open question to what extent this large number of early voters is made up of people who would have voted on Election Day anyway,” Downey said. “It is really hard to gauge the party success until we get the final canvass.”