Dyno Guesses & Bench Racing Forum - compression difference equation to hp?

When I do my heads, my compression will be changing - going from 10 to 10.5 I believe.
all other things being equal, how much hp or % increase in power does that equate do?

Im pretty sure I had seen before that one full point equates to about 3% difference... but not sure that is accurate, just remember seeing that a week or two ago. Maybe someone else will chime in.