For some real historical context, here is a page I scanned from the 1910 census which shows a remarkable factoid. If you work it out, at the time over 40% of the men (age 20 and over) in the City of Pittsburgh were foreign born.
For more on the international theme. If you know your German here is a clip that ran just before the primary on German Public Radio that was mostly focused on Pittsburgh. Gebeutelt von der Globalisierung Wirtschaft dominiert Pennsylvanias Vorwahl.
and could you come up with a better addendum to all that. First the Spanish buy Kennywood and now the French are buying Yellow Cab. I can't wait to see what Messrs Carbolic do with that little factoid.