Here are the top 100 ranked according to kills per root game.

KPRG Player
15.76 aalanda
12.84 Hennessy
12.26 Noobie
11.91 wertrew
10.90 diceptr
10.70 Rastaa Man :)
10.42 gogi
10.31 dicehead
10.19 rabbidmonkey4
9.98 cadpilot
9.83 Seth Miller
9.56 Hong Kong
9.22 Rafkrik
9.01 nessa
9.00 glut123
8.93 toms
8.91 Juhokki
8.48 stakaboo
8.41 Kurt_Russell
8.37 jf220
7.93 angel30
7.89 axlehammer
7.69 Beach_Bum_13
7.63 AlexKon
7.61 BenJa LeZana
7.54 Thrilltokill
7.39 Mr.Mosgood
7.32 Nerd Alert
7.29 IFIGENIUS
7.27 tera santa
7.18 Im Defeated
7.11 djefferson
6.94 jsonproxy
6.92 Fatman_x
6.90 yes me
6.78 OneShot7
6.57 Zigua
6.48 Lalita Lani
6.47 rocka09
6.36 Gdott
6.35 awesmotness
6.33 bivo
6.26 Tiramisue
6.15 ChalkdustTorture
6.08 fish28
6.06 michele
5.98 panzer
5.95 Cafterdeath
5.87 Verano73
5.79 @jeremywright
5.70 spman
5.70 2devi
5.56 hcdug
5.46 Troy11
5.43 tryin'
5.22 negramarta
4.93 N00bSCH001BU5
4.86 Sian85
4.75 Gurgi
4.65 kudos
4.64 spman2
4.60 Gauntlet15
4.53 Buttwank
4.40 Rsquared
4.30 rofarah
4.30 Soromon
4.23 {A}Monkey SLayer
4.15 k?lllll
4.15 Whitehawk
4.11 shadolin
3.90 Dude111
3.77 Cambria
3.76 Marcysch
3.49 parsifal
3.38 Maze78
3.33 masticore
3.30 greenman
3.08 moulue
3.05 apignarb
3.03 kakku man
2.96 Who'sNutz?
2.96 sw1ft25
2.94 Mitsi the cat
2.94 ehervey
2.93 ijustwanttoplay
2.74 HeavyMetalManiac
2.63 Laanos
2.60 Kekko2797
2.25 Skerdikas
2.07 fletch85
2.00 longpube
1.74 beevoh
1.41 fair_player
1.30 vino_en_carton
1.14 gameboy
1.03 franklyghost
0.72 jurgen
0.58 Jo-Joo
0.44 PRESIDENT N° 1
0.00 elvissey