They don't tell us much if you base them on PK stats. Dozens of people will play something to 10% of its pk potential, not just for reasons of different ability but also how they enjoy playing the game, hundreds will play and delete without a pbf.

I don't know exactly how I would want to base statistics off of pbf'd pk records here.

Unrelated but, if you like statistics, this was a fun read:
http://rsos.royalsocietypublishing.org/content/4/12/171085