Story highlights Early voting stats offer hints of good news for Clinton in Arizona, Nevada and Florida

The statistics show Trump is outperforming Mitt Romney in Iowa and Ohio

Washington (CNN) Hillary Clinton's campaign has reason for optimism in several swing states -- and appears to have turned Arizona into a battleground -- as millions of Americans vote early.

More than 7.3 million Americans have already voted. Democrats have improved their positions in North Carolina, Nevada and Arizona compared to this point in 2012, according to a CNN analysis of the latest early voting statistics.

Republicans, meanwhile, have good news in Iowa. Republicans have improved their position there over 2012 -- backing up the polls which suggest it could be the easiest state won by President Barack Obama for Trump to flip this year.

And in Florida, where the latest comparable data comes from 2008, Democrats -- buoyed by an increasingly diverse electorate -- have cut deeply into the traditional Republican advantage in early ballots cast so far.

These findings represent absentee ballots submitted and early votes cast through Tuesday across 35 states where data are available. Catalist, a data company that works with progressive candidates and advocacy groups, academics and think tanks, connects the data to voter records, allowing a deeper look at who has already cast a vote in this year's election.

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