% Drop Rate?

[Ludwig-von-Mises-I]

I have a question. What is the Drop Rate from killing creatures?

I think i'v figured it out by doing some calculations on my calculator but i'm not sure how much your level changes your drop rate percent? Or maybe the type of creatures you kill, plus level, plus the type of quest? Quests keep count of your kills so this is way i'm asking maybe the quest changes something too?

Well i think the best people that can answer this are the developers etc so this is really a question to them for the most part.

Thanks for reading.