Here are the number you take it from...
What you do is you find out your total games played, after you play a game you can see wins and losses then put those together...
In my case i have 244 wins and 228 losses... That gives me 472 games played.. My total takedowns are 6894, but that includes towers.. So i take one tower off per game so all in all it is.. 6422 takedowns...
At last i take 6422 and divide it with 472 and get kills per game... My kills in average each game is 13,6, which is considerablu higher than i expected, which is probably why i have Platinum in Takedowns...
So what is your average kills per game?