Thanks for the info, guys. Yeah, the first several I picked up were pretty worn in that area and I even said outloud to myself "What a dumb place to put the mintmark!" But then I found some that were in really nice condition on the back and I couldn't see one there either. So P explains it! Is it that way on most coins? If there's
no mint then P is the culprit? Or can it be D or S depending on the coin type/date?