Not on hand, but that was the first scholarly article I found in the top 5 results after a 30 second Google search. It does mention this though, as I'm sure you read:

Forty-one percent of the transgender persons in the United States attempt for suicide at least once in their life.[8] In San Francisco, the prevalence of attempted suicide among transgender persons is 32%, among young age (<25 years) it is 50%.[9] Suicidality and self-harm behavior are serious problems among sexual minorities in Japan.[10] Transgender persons are at higher risk for suicidal ideation and suicide attempts at Virginia.[11] Fifty percent of transgender persons in Australia have attempted suicide at least once in their lives.[12] In England, 48% of the transgender young people had attempted suicide at least once in their lives.

There's no doubt external factors have their affect, but what I find interesting is the statistics are still very similar in a place like San Francisco which is known for their acceptance of LGBT.