This US Census report has already made the rounds, but the findings bear repeating. From 1995-2000, Pennsylvania was 47th in outmigration rate (includes DC). Migration rate controls for state population. Michigan was 51st and Ohio was 49th. Relatively speaking, people are NOT leaving the Rust Belt in droves.
The problem for the Rust Belt is the rate of inmigration. Pennsylvania had the 46th lowest rate of inmigration. Perhaps surprisingly, California was 50th.
Concerning net migration rates, Pennsylvania was 37th. The big winners are the usual suspects: Nevada, Arizona, Georgia, North Carolina, and Florida. Nevada had the 5th highest rate of outmigration. Colorado was 10th. If you remember, Georgia currently works hard to retain its high school graduates. From 1995-2000, Georgia was 30th in rate of outmigration. Georgia was 10th for inmigration. Looks as if Georgia reacted strongly to the new immigrants.