1 in 70 of the 15 - 24 age range and 1 in 909 of the 65 + age range, suggests to me that this is little more than a fashion, because I doubt whether people change so significantly as they age.
I am in the latter age group - I remember my teen age and early twenties years very well still and remember how awkward many of us were at that age, but I can't think of anyone who said they were trans. It just wasn't a thing.