http://nwn.wikia.com/wiki/Experience_point
Realms of Annakolia used the base XP tables provided by Bioware - nothing is modified in any way - Cave Bats have raised CR to help new or low level players easily level to the double digits.
Quoting from the NWN Wiki:
in:
Game rules, Character development
Experience point
Edit
Share
Experience points (XP) are an abstract measure of the experience, knowledge, and training that a player