Since I don't have any say in this I'll give an idea.
Academy Students:
If they get a mission higher than their rank mission they gain lets say about +20,30 exp
Genin:
The same thing but they get +40,50
Chuunin:
The same thing but they get +60,70
Jounin:
The same thing but they get +80,90
Anbu:
The same thing but they get +100,110
Legendary Sannin:
The same thing but they get +120-150
(Skips Kage because that isnt a real rank)
KuroKage:
The same thing but they get +160-200