What is the shot percentage of shotgun chokes?

That is the percent of shot that will stay inside a 30 inch circle at 40 yards. Table of percentages below for 12 g. Percentages remain about the same for other guages. although the measurement of constriction would be different.

Standard American*Constriction (12 gauge)Pattern percentageCylinder.000 in40%Skeet.005 in53%Improved Cylinder.010 in57%Modified.020 in67%Improved Modified.030 in73%Full choke.040 in75%