220 watts usually buys me 19.5-20 mph with ~50 feet of climbing a mile at 165 lbs in not-super-windy conditions with an aero bike and fast tire setup and generally more-aggressive riding position. 250 + watts is more in the 20.5-21 mph range. 200 watts is more in the 18.5-19 mph range.
Lots of qualifiers there, because lots and lots of things affect speed at various power outputs.