I always thought there should a better metric than punts down inside the 20. Perhaps this has already been done, but I calculated a new metric for punters, called Possible Punt Yards (for now until I think of a better name). It takes the total possible yards they could punt, minus return yards, to get a possible punt percentage. So if you are punting from the 50, there are 50 possible yards, and if you give up a 10 yard return, you're PPY% would be 80% (50-10/50).
Looking at the 2011 season, Brett Maher had a 60.54%, which is pretty good. Don't know if it made a difference, but in losses his PPY% was 3% less than in wins. It definitely made a difference in the NW game, as he punted a remarkable 89% gross possible yards, but gave up 40 return yards, which were key in a close game. I have the 2010 stats somewhere as well, will have to do a comparison with Alex Henery to see how is PPY% looked compared to Maher.