Android game size

I am having trouble finding some good game size reduction tutorial or explanation for android.
If I create just some empty android project and deploy it on android it size is like 9 MB. I don’t think that “Reducing File Size” chapter from official unity manual much helps here. But some games like DiceBall or KollapsLite, that are made in Unity, on my android only takes 548 and 312 KB.
Please somebody tell me what am I missing here?

The app takes much more than 548, 312kb. The size is displayed like that because the data is stored on the memory card

The android OS store the application in memory card so thats why it does not need to reduce the size of the game.