That is not normal. My Android OS only uses 8%. It sounds like you have a app that is keeping your phone awake or actively running. I had this with a Samsung app that had an update but would not notify of such. I found about the update when I opened up the app.
Sent from my Samsung Note II using Android Central Forums
I've had my Note 2 since November and about two months ago I noticed my battery life began declining at a faster pace than normal. I rooted it and am running CleanRom and I'm back to being able to use it all day long without getting battery warnings in the evenings. Some nights I can go without charging it.