Notes:
We can calculate that about 1 in 3000 US residents have had or will have SRS at some time during their lifetime.
Since SRS is only done on adults, we can divide the annual number of surgeries (1237) into the number of eligible US adults age 18-64 (174 million.)
This tells us that 1 in 140,000 US residents have SRS each year.
Since each of us has 47 years to have SRS, and the SRS could happen in any one of those years, dividing yields 2996, or about 1 in 3000.
It is estimated that only about 20% of MTF transsexuals who transition will have SRS, but that about 80% of FTMs who transition have top surgery.
Thus, about 27% of all those who transition have SRS, so about 1 in 800 US residents have GID severe enough to transition.