Early Voting Results 2012 - Swing States: Democrats Have Good Lead in Crucial Florida, Ohio; 30 Million Americans Have Already Voted

While the presidential election is tomorrow, many states allow early voting, and over 30 million people across the country have already cast their ballots.

Early votes tend to be a boon for Democrats, as their constituency is more likely to have difficulty getting to the polls on Election Day, either because of work, children, health concerns or transportation issues.

In 2008, 39.7 million voters cast early ballots, representing 30 percent of all ballots cast in that election. That was a significant increase from 2004, when only 20 percent of voters cast ballots before Election Day.

This year may not continue the trend, as turnout may be lower overall. That could prove to be a boon to Republicans in crucial swing states.

None of the votes will be counted until Election Day tomorrow, but according to the Associated Press, these are the party affiliations for those voters who have already cast ballots this election in the most important swing states:

Colorado - 1.6 million votes
Republicans: 37 percent, Democrats: 35 percent
Advantage: Republicans +2 percent

Florida - 4.3 million votes
Democrats: 43 percent, Republicans: 40 percent
Advantage: Democrats +3 percent

Iowa - 614,000 votes
Democrats: 43 percent, Republicans: 32 percent
Advantage: Democrats +11 percent

Nevada - 702,000 votes
Democrats: 44 percent, Republicans: 37 percent
Advantage: Democrats +7 percent

North Carolina - 2.7 million votes
Democrats: 48 percent, Republicans: 32 percent
Advantage: Democrats +16 percent

Ohio - 1.6 million votes
Democrats: 29 percent, Republicans: 23 percent
Advantage: Democrats +6 percent

Total in swing states: 11,516,000 votes
Democrats: 65 percent, Republicans: 35 percent
Advantage: Democrats +30 percent

Ohio's percentages for both parties are low because party affiliation either couldn't be identified for many voters or the voter identified as independent.

Democrats lead in the early voting numbers in every swing state but Colorado, and in these states they lead by a huge margin.

However, while early voting data can give some clues as to how the rest of a state will vote, it isn't necessarily reliable. And since early voters tend to be Democrats, we may see a surge of Republican voters tomorrow.

Also, if the election is very close, states need to count absentee ballots, which tend to skew Republican, as many of those ballots come from military personnel stationed overseas.