Shifting Party ID in Pennsylvania

A Democratic tilt in partisan views among Pennsylvania voters may have been one of the motivating factors beyond Sen. Arlen Specter's surprise party switch: In 2008, Democrats had their biggest advantage on party identification in Pennsylvania in nearly 20 years.

Here's the list of voters' party leanings in Pennsylvania from exit polls dating back to 1990.

       Democrat   Republican   Dem.-Rep.   Ind/Other 
2008      44          37          +7          18
2006      42          38          +4          20
2004      41          39          +2          20
2000      40          40           0          20
1998      43          40          +3          17
1996      42          39          +3          19
1994      39          40          -1          20
1992      42          38          +4          20
1990      45          34         +11          20
1988      40          42          -2          18

***Update***

The Pennsylvania Secretary of State records party registration information about the state's voters, and their figures over the past decade show a similar pattern: Between 1998 and 2008, Democratic registration jumped by 860,552 but Republicans just 96,895; others went up 336,061 over that period.

p.s. Thanks to Jim Burton of POS for pointing out earlier typo in table, and for suggesting a look into the official figures from Pennsylvania.