It sounds like you misunderstand the fact that being trans has a stigma attached to it and the same percentage of the population has always been trans but more

It sounds like you misunderstand the fact that being trans has a stigma attached to it and the same percentage of the population has always been trans but more are comfortable coming out as trans now. The percentage is not actually changing. It's the same as coming out of the closet as homosexual, people used to get beaten and killed for it but not as much anymore in the US. That's what stigma does and public perception has been changing to be more accepting, that's all.