Recon as it is sniping etc, need a good aim. Assault 1/3 hits because of the recoil etc, same goes with engineer but engineer weapons usually quite inaccurate, especially at long range. Support is weird - 20% seems okay but when you shoot it gets more accurate hence the 40%..
Agree with kyle apart from assault, should be 40%+ bearing in mind you can wield the krylov, baur and scar (which is suprisingly accurate believe it or not)
Edit:
Kills per round varies - as some people play on:
High point maps: 40+ Low point: 20+ Titan: 100000000000's
Accuracy dont mean a thing unfortunatly, unless you go for that one sweet shot. I have a lowish accuracy (20something%) Because i just shoot random things, crates, empty vehicles, the sky, etc. Kills matter
Small hourglass island Always raining and foggy Use an umbrella
The last thing you should think on when you play is your accuracy.
And leetkyle 20-40% with support? hehe if you have over 30% you´re most likely terrible afraid of shooting at people unless they are afk and withing 10m from you.
I dont play 2142 but I think that accuracy means absolutely nothing. For some weapons, you will do better spraying (because the rate of fire and damage/bullet are high) than wait between each shots. So you will get bad accuracy but you will be able to kill anyway.
kills per round can be skewed by playing titan alot since rounds are very long.
kpm more relevant stat with a kpm > 1 being pretty good. however, even kpm can be skewed if you play alot of 64 player city maps.
accuracy is the most irrelevant statistic when you look at it globally because you are comparing apples and oranges. rather look at your accuracy with individual weapons to see how you are doing...but even then it doesn't matter sometimes cause people will fuck around and shoot at butterflies since it is only a game!