I didn't include the Alchemic, Animal, Cooking, Gathering, Growing, Industrial, and Intellectual skill speed ups because they're boring.
For reference, here is the breakdown:
I: Unspecified, it just says it improves it., 400i
II: 5%, 1250i
III: 10%, 5000i
IV: 15%, 10000i
V: 20% 20000i
Edit: Now with categories.
Corrections and additions are encouraged.