How many there are of us?
Nowadays, maybe 20.000 exile-Tibetans, plus those ALL who no longer can say they are Geluk, or rather do say they are Geluk, but who nevertheless stay clear of the Protector of this very lineage, in public at the least. And also, plus all the US, the Westerners, even MORE.
Before the DL wanted to spread the Dharma by speaking against the Dharma, most Gelukpas were us, the Shugdenites, and then it was between 400.000 to 4.000.000. (You see, without the ban, there was no need to know who of us practiced like this or that, so we simply do not know.)
But as for the current situation, nobody knows. And if you make a poll, nobody dares to agree. Well, some of us do dare, but we are not very popular.
So, as to your question, nobody can help.
(My wink, to the historical situation, is that take the total of Tibetan Buddhists, not Tibetans as an ethnic entity, but as a religious entity, including Mongolia and some Chinese areas, and take aboutish 70% of those to be Gelukpas, and from those, take the same 70% to be Shugdenites. That is the approximate amount of us, prior to the Chinese invasion and the Dalai'ite dharma-spread.)