The actual ‘City” of Philadelphia is basically 4 large areas....
1.South Philadelphia (mostly Italians / big time old time Democrats
2. North Phila / West Phila (mostly all black)
3. Center City (upper class whites / liberal / and blacks)
4. Northeast Philadelphia (mostly all white / mostly Democrats and some Republicans)
90% of the state is probably like any rural state, but the cities of Philadelphia and Pittsburgh are probably 95% Democrat, and Philadelphia alone usually provides a 350,000 to 600,000 + vote margin alone in Democrat votes, which have to be overcome by rural or suburban Republicans.
The big counties to watch in the Philadelphia are would be:
Bucks County outside NE Philadelphia,
Delaware County and Chester County outside South Philadelphia
Montgomery County west of Philadelphia
If the Romney can win big in the above highly populated Phila suburban counties, he might have enough from the rest of the rural counties in the rest of the state to pull it through.
Turnout for Phila has to be low also.
Romney can win Bucks by a solid margin this election I think. Delaware and Montgomery Counties have moved to the Dems though but I think he can down their margins quite a bit.
Jame Carville once said Pennsylvania is Philadelphia and Pittsburgh with Alabama in between.
I assume you mean less than 125%?