What percentage of the population of the US is transgender?

Answer 1

This is a new area of study, and there aren't many statistics available yet.

For transgender people

As 2016 there is a report (Gates, 2016) that finds the number to be 0.6% of the population, double the 2011 number, representing 1.4 million Americans. This number will necessarily be quite low because many trans people will decline to be surveyed, many are not yet self-identified for a variety of reasons, and the Williams Institute only looked at adults 18 and over.

The apparent population doubling seen from the 2011 to the 2016 report is likely due to increased awareness amongst the trans population and improved survey techniques. (As a measure of the former, applications to gender clinics have been roughly doubling, year over year (Lyons, 2016), for several years now. Transgender medical services in many countries are increasingly swamped.)

It seems quite likely that we’ll see another big jump in the estimated population with the next report.

For Genderqueer people

There aren't any large scale studies yet. But according to Huffington Post, there was a study called "The National Transgender Discrimination Survey (NTDS)" which was a joint project of the National Gay and Lesbian Task Force and the National Center for Transgender Equality, provided the opportunity for survey participants to identify their gender as “male,” “female,” “part time as one gender, part time as another,” or “a gender not listed here.”

Most survey participants identified as “male” or “female,” but over 800 (13 percent) selected “a gender not listed here” and chose to write in their own gender. “Hybrid,” “either/or,” “both/and,” and “mosaic” are just a few of the ways these genderqueer participants described their gender.

Answer 2

I heard that it's about 1/10,000 for mtf and 1/30,000 for ftm.

Answer 3

0.6%

Answer 4

0.3%