If the season ended today, Pau Gasol would have the best three-point percentage of any player in a single season in NBA history.
He has a current average of 54.7%, this is, 52 shots converted out of 95.

For the moment, the 3 best averages are:
1.Kyle Korver with a 54.6% (season 2008-2009)
2.Steve Kerr with a 52.3% (season 94-95)
2.Tim Legler with a 52.2% (season 95-96)

Gasol's average is still better if you only take into account the stats after the Allstar break. Since then, Gasol has an incredible average of 61.5% (32 out of 52).

We still need to see those averages when the playoffs come and the defences get stronger.