title: How to count average "kill score" of mobile app users with flurry
body: <p>Let's say I'm developing a mobile game where you have to kill zombies. I'd like to use Flurry Analytics to track the number of zombies that the average user kills. I ask because I want to build an in app purchase to allow users to buy more bullets, but first I need to know how many bullets to give for free, and this depends on how many zombies the average user kills (and I already know that it takes 5 bullets per zombie).</p>