Dex remains twice your level until level 40.
Once you hit 40, raise dex to 80, then EVERY level after that, add one dex.
Thus, your dex will then be your level +40.
Luk recieves all other points that have yet been used.
This is the most common build as it allows for the most damage capable, whilst being able to wear all current level equipment.
BTW, stats and skills are two different things.