An early withdrawal from a retirement account (1099R, box 7 coded a 1or 2) is taxable on a PA income tax return to the extent that the withdrawal exceeds your cost basis in the plan. Your cost basis is the sum of all your contributions into the plan (does not include any employer contributions or earnings) less the sum of all previous distributions from teh plan. Some retirement plans will show this figure on the periodic statements you receive. Or you may need to contact the plan administrator for the figures.
See: https://revenue-pa.custhelp.com/app/answers/detail/a_id/1470/~/how-do-i-know-if-the-amount-on-my-109...
