Early Voting Battleground Tallies

Nov. 6, 2012— -- Polls may have opened nationwide this morning, but the election has been under way for weeks, thanks to early and absentee voting, and millions have already cast their ballots.

It is expected that 46 million people will vote before Election Day this year, and their votes will make up roughly 35 percent of the total votes cast in this cycle.

That's an increase from 2008, when the total early and absentee vote was roughly 40 million and accounted for 30 percent of the total votes cast.

Out of the eight states that ABC News currently considers "toss-ups" -- Colorado, Florida, Iowa, New Hampshire, Nevada, Ohio, Virginia and Wisconsin -- all but New Hampshire allow for some form of in-person early voting.

(New Hampshire only allows mail-in absentee voting for those who can't make it to the polls on Election Day.)

Four of the states -- Colorado, Florida, Iowa and Nevada -- register voters by political party, so their early vote count includes a party breakdown. In three of these states -- Florida, Nevada and Iowa, Democrats have a slight advantage in terms of early votes, while in Colorado, Republicans have the advantage.

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But the vote is close in all these battlegrounds, and in each one voters registered as "no party" or "unaffiliated" -- more commonly called independents -- make up a sizable percentage of the voting population, which heightens the uncertainty about who is actually ahead in the final, crucial hours.

Below is a breakdown of where the early vote count stands in these battlegrounds, and how it compares with the early vote in 2008.

COLORADO

2012:
1,872,987
Dem -- 34.3%
Rep -- 36.1%
Other -- 29.6%

2008:1,704,820
Dem -- 37.7%
Rep -- 35.9%
Other -- 26.4%

FLORIDA

2012:
4,469,393
Dem -- 42.9%
Rep -- 39.1%
Other --18%

2008:4,377,774
Dem -- 45.6%
Rep -- 37.3%
Other -- 17.1%

IOWA

2012:
640,248
Dem -- 42.3%
Rep -- 32.1%
Other -- 25.6%

2008:481,179
Dem -- 46.9%
Rep -- 28.9%
No/Other -- 24.2%

NEVADA (reports numbers by county -- numbers given for Clark County, the most populous in the state)

2012:Clark County
484,363
Dem -- 47%
Rep -- 33%
Other -- 19%

2008:561,776
Clark County
Dem -- 52.0%
Rep -- 30.6%
Other -- 17.4%

The 2012/2008 early vote numbers in battlegrounds that don't register voters by party affiliation:

OHIO

2012: 1,791,334
2008: 1,456,364

VIRGINIA

2012: 427,987
2008: 465,962

WISCONSIN

2012: 412,611
2008: 633,600