I think it took me around that many codes to get my first die-cut, and I seemed to get a few of them fairly close together. I don't think I've dug up many cards from the 60s either. I'm sitting at 30 digs right now.
I've entered 70 codes. I hit on 8 or 9 die cuts and managed to collect the whole Rangers team set (I traded for the Nolan Ryan offline). I also have a Tony Gwynn that I've already traded even though I don't have it yet. I've got 5 cards from the 60s with the oldest being a '61 Coot Veal.