I did a Google search and found a weight watchers forum where a woman asked what size your calves and thighs are, along with weight and % body fat. 221 women responded with their measurements. I put this data into a spreadsheet and figured out what boot cuff sizes should be:
XS - 12.5" - 11% of adult American women
S - 13.5" - 24% of women
M - 14.5" - 30% of women
L - 15.75" - 20% of women
XL - 17" - 11% of women
For example, if your crocheted boot cuff stretches from a minimum of 6.25" to a maximum of 7.25" when flat, it will fit up to a 14.5" calf, and 65% of women will be able to wear it.
These five sizes will fit at least 95% of adult American women.
We're exploring how to knit boot cuffs that stretch to fit all adult women, yet don't look sloppy. This involves a knitting ribs. We're trying acrylic, wool/acrylic, and yarns with an elastic thread.
I don't know how large girls' calves are.
There was little correlation between calf size and height or weight.