Unfortunately Apple doesnt allow apps to see that kind of data. It is a bit annoying, but I understand why apple doesnt give developers access to see what apps people are using, and how much they use those apps. That seems like it would be a huge privacy issue.Does this app show you the apps that are effecting battery life the most? (similar to the iphone app)
The only way we might be able to see that data is if apple implements it themselves (like on the iPhone)