As I do after every season I look at every punt in the NFL and grade them based on how many yards the punter “gained” relative to how many he could have gained. Punting is about field position and the job of the punter is to maximize field position - to make the opposing team start their drive with the worst possible field position.
To do this I break up punts into to groups - long field and short field punts. Long field punts are punts where the team is punting from inside their own 35. On long field punts the optimal result is 65 net yard punt.