What do steal settings correspond to in 1-20 chances?

[LA Bear]

Very Aggressive = 1 to a
Aggressive = 1 to b
Normal = 1 to c
Conservative = 1 to d
Very Conservative = 1 to e

I'm thinking it's something like
a=9, b=11, c=13, d=15 and e =17

Does anyone have a better grasp on HALs truth table?