[CureeusCPL57]

Here is some interesting statistics about size:

Percent Length
0.2 percent 3.75 inches
0.3 percent 4 inches
0.2 percent 4.25 inches
1.7 percent 4.5 inches
0.8 percent 4.75 inches
4.2 percent 5 inches
4.4 percent 5.25 inches
10.7 percent 5.5 inches
8 percent 5.75 inches
23.9 percent 6 inches
8.8 percent 6.25 inches
14.3 percent 6.5 inches
5.7 percent 6.75 inches
9.5 percent 7 inches
1.8 percent 7.25 inches
2.9 percent 7.5 inches
1 percent 7.75 inches
1 percent 8 inches
0.3 percent 8.25 inches
0.3 percent 8.5 inches
0.1 percent 8.75 inches
0.1 percent 9 inches

So the average penis length is 6.16 inches.
The average girth is 4.84 inches.

More recent studies have produced the following results:

A sample of 60 men studied by researchers at the University of California at San Francisco determined that the average size of their erect penises was 5.1 inches long and 4.9 inches in girth. A Brazilian urologist who measured 150 men reported that the average size of their erections was 5.7 inches long and 4.7 inches in girth.