According to voter registration statistics from the Pennsylvania Department of State as of Oct. 22, the number of party switches to the Democratic and Republican parties have fluctuated since the 2008 election. There have been 163,462 switches to the Republican party and 125,396 switches to the Democratic party. However, voters have been changing parties more dramatically than ever in the past 12 months.
From November 2008 to November 2009, there were more voters switching to be Democrats than to be Republicans in Pennsylvania.
But from November 2009 to February 2011, Republicans saw a clear upward trend in voters switching into their party.
The Democratic party since February 2011 saw a steep increase in voters changing affiliation to be Democrats. For example, in the period between January and February 2012, there were approximately three times more voters switching to the Democratic party than the Republican party.
To add to the volatility, Republican numbers have soared in the last two months before voter registration closed in October.
So far in 2012, both parties have seen a steep relative increase in total amount of party shifts. The highest was from September to the voter registration deadline on Oct. 9, with about 26,500 switches.