That would depend on a lot of variables. Such as air charge temp, air flow through through the intercooler and IC pipes, flow through the heads and valves, flow and/or backpressure in the exhaust, present state of tune.
Just way too many variables to say X amount of boost = Y amount of horsepower.
Boost pressure is really just a measurement of backpressure in the system that the supercharger is pushing against.