http://www.basketball-reference.com/players/r/rondora01/shooting/2013/From 16 feet to the 3 point line, he's shot .556% out of 35/63 shots.
In contrast, Kevin Durant has taken 65 shots from that area and hit .385% of them. Chris Paul has taken 69 shots and hit .449% of them. Paul Pierce has taken 68 shots and hit .412% of them. Steph Curry has taken 118 shots and made .449% of them.
Last year, Dirk made .516% of his shots 16 feet-3 point land.
If you actually watch the games, you can see that Rondo is stroking. His jumpers are starting to become more and more contested, and he's been making them. He's hit many difficult mid range shots this season, and has drastically improved. Last year, he was .413% from the same area.