If you ask most trans people why the numbers are going up you'll typically get the same response: awareness and exposure to other trans people that can help explain gender dysphoria.
Many trans people do not understand that they are suffering from gender dysphoria. It's not a crystal clear set of symptoms. They will rationalize or bury symptoms, which are more or less entirely mental, and it is frequently not at all apparent to an outside observer that they are experiencing it.
I distinctly remember the first time I read a forum with others describing gender dysphoria and how it manifested for them. I discovered that feelings I thought were something only I felt, that no one else seemed to understand, actually had a root cause which was shared by others. That there was a name for what was "wrong" with me, and that I could fix it. I was 26.
Awareness about gender dysphoria has risen and more people are finding out that there is a name and a solution for the wrongness that they experience. It's only natural that more trans people are coming out.
It's unfortunate that cis people cannot experience what gender dysphoria is like, even for a moment, because they have no frame of reference for why it is so confusing for trans people, especially prior to them realizing what it is that they are experiencing.
Eventually things will level off as the number of people with gender dysphoria that have recognized and treated it approaches 100%, though I doubt it will come to rest anywhere near there.