My mother always did say my sister's size 7 feet were extraordinarily large. Now she's practically average.

...[A]verage female shoe size has increased to a size six over the last 10 years, and demand for size nines has triggered an 80 percent increase in stocks at the department store, Debenhams reports.

The change is attributed to women's feet becoming broader rather than longer - experts believe this may be due to an increase in average body weight.

...
"High fashion shoes such as stilettos in larger sizes have to be made much stronger with sturdier load bearing points, able to cope with greater levels of stress and wear."

Reminds me of the plot to Kinky Boots (which, just between you and me, wasn't all that great of a movie).