You can download the latest VR report for PA here.
The most current VR change document is here, but has nothing to do with comparing to 2007.
Those first two documents are in EXCEL format.
You can also download the VR report for PA from May 2007 here. (.pdf)
All I do is input the verified data into an excel spreadsheet and voila, the math is done. These are the current numbers on PA as opposed to 2007:
So, currently, DEM enrollment is at 50.82%, GOP enrollment is at 37.04%. This means that the Democratic party currently has a +13.78% enrollment in the Keystone state. At this time four years ago, the Democratic party only had a +7.56% enrollment edge.
As for that enrollment change report that I linked to above, if you download it, it shows weekly changes to each party and where applicable, from which other party the changes came. For instance, for the last week listed, the Democratic party picked up 16,489 voters, the Republican party picked up 13,916 voters. Sounds pretty even until you see WHERE they are getting the new enrollment from: the Democratic Party picked up 10,077 former Republicans, while the Republican party picked up 10,190 former Democrats. So, actually, the GOP had a slight advantage in this week. But in the unaffiliated cross-overs to party declaration, the Democratic party won almost 2:1. It picked up 6,155 former unafilliateds, but the GOP only picked up 3,569 unafilliateds and amazingly amazingly enough, the Democratic party picked up more former Libertarians than the GOP in this week.
Now, none of this is guarantee of a vote, but the tendencies of a state can be watched and measured. And the Keystone state is absolutely pioneer is making these statistics available for everyone.
I also published a VR statistics entry for PA in 2010. Published 03/13/2010
There was a higher percentage of registered democrats in PA than now (it was as 51.14% in early 2010), but historically, for correct comparison, the Democratic Party in PA is ahead of where it was 4 years ago.
VR statistics in more than 28 states. Published: 10/04/2008