[3rd&Brown]

I found some statistics from a 10 year old study from the Delaware Valley Regional Planning Commission on commuting patterns in this region.

4.57% of Mercer County residents work in PA
4.68% of Mercer County residents work in states "other than" NJ or PA (presumably NY).
So arguably, there is an almost exact even "pull" in terms of commuting patterns.

9.34% of Bucks County residents work in Central and North Jersey (mostly Mercer and Middlesex Counties)

0.62% of Philadelphia residents work in Central and North Jersey (mostly Mercer, Hunterdon, and Middlesex Counties).