I am constructing bb vs sb calling range and trying to take rake into account (I play nl200).

When opponent raise 3bb I need hand with at least 2bb/6bb = $4/$12 = 33.3% equity vs his range for profitable call. Here for simplification I asume I can release 100% of my equity. 

Now I look for all my bb vs sb calls this year and find out I called 1500hands and paid $750 of rake, so $0.5 rake per call bb vs sb.

Any ideas how to change formula to take rake into account?