City and Suburb
But a side note on the differences between city jobs and elsewhere,in 2004 (and in 2004$) the average annual pay for a job located within the City of Pittsburgh proper was $42,834 while the comparable annual pay for jobs located in the suburbs was $31,676. So its not just the number of jobs that have been retained in the city proper, but the relatively higher paying jobs in the region as well.
The really remarkable thing about the number jobs located in the City of Pittsburgh is how stable it has been over not just recent decades but almost half a century if not longer. Jobs located in the City proper in 1960 were nearly identical to the 300K or so jobs that are located in the city today. When you consider just how much population has declined in the city, that is a remarkable factoid. As people have moved out, but kept their jobs within the City, one obvious result has been increased commuting. Here is a map of commuting patterns of workers whose jobs are located in the City of Pittsburgh proper as of 2000.
or in the angle Harold was discussing, here is a map of Allegheny County in terms of Jobs per square mile by municipality, also as of 2000: