Revenue for individual apps?

I'm relatively new to the App Store (not new to Objective-C, though) and I'm wondering how easy it is to track how much money each individual app you have in the app store is making.

I have an App in the store already, and I haven't received any sort of income statements yet so I don't know how they're split up, but I have a friend who wishes to work on my next project with me - we want to split the profits 50-50.

Say I have two apps in the app store, is there a way to find out how much each app is making, if they both use the same revenue models (fremium, iAds w/ IAP)?