>>81524257>6.5"x5" is common for whites and a bit under average if you take away the minorities shitting up the average in the west.Ignoring the goalposts of "sex having" for now.
Assuming that 6.5 x 5 is the true average for whites (you say even a bit under) and knowing CalcSD's western average of about 5.8 x 4.75, for non-whites to bring down the "true" average to the CalcSD numbers they would have to average about...
In a population of 10% non-whites
-0.6 x 2.5
of 25% non-whites
3.7 x 4
of 40% non-whites
4.7 x 4.4