There's someone over at electproject.org that is accumulating mail-in ballot request and return statistics. All of the normal disclaimers should go along with these numbers. Instead of having a unified voting system, like most sane and civilized countries, we have 50 different sets of voting rules and data collection and reporting methods. So gathering up these numbers has got to be a pain and are only as accurate as the sources.
So numbers are just starting to trickle in, but this should give you an idea of just how important GOTV GOTV GOTV is.
State % requested % returned % of 2010 total ballots
by party by party cast
Florida D 38.8 D 31.5 2.3
R 42.1 R 50.4
I 19.1 I 18.0
Florida 2010 total ballots returned by party D-36.5 R-49.2 O-14.3
Iowa D 46.7 D 49.7 7.4
R 33.4 R 34.5
I 20 I 15.8
Iowa 2010 total ballots returned by party D-43.7 R-38 I-18.3
These numbers can be considered an early vote. So roughly 2.3% of Florida's votes have already been cast, and 7.4% of Iowa's vote has already been cast. Florida is doing worse than 2010 and Iowa is doing better.
The more Dems that vote early, the more resources we'll have to get more Dems to vote on Nov. 4.
GOTV! GOTV! GOTV!