Re: numbers, I know there is concern about the reliability of the census data, but using data from people who actually specified a gender identity, a third answered that they are non binary, or have a gender identity that isn't man or woman.
It therefore seems clear that a very significant number of trans people are neither trying to pass as the opposite sex, nor hiding the fact that they are trans.
Also, that if the goal is trans inclusion, it's not clear how they are helped by masculine/feminine gender segregation.