Nexus 7 battery drain

https://docs.google.com/open?id=0B_xbHNV5FwfLbTlVOHI0NFpkV0E

https://docs.google.com/open?id=0B_xbHNV5FwfLbEI5bXRrNzlEME0

Steep drop, only 20 some hours on battery. The device is idle, not used. Hardly any apps running. The OS seems to be chewing up the battery. Ideas?