How many active pilots are there in the US? How many are women?
According to the FAA, as of December 31, 2016, there are:

584,361 Active pilots (39,187 are Women pilots, or about 7%)

104,382 Flight Instructors (6,848 are Women Flight Instructors, or about 7%)

The ratio of female instructors to female active pilots is virtually the same as for males.