I would put the number at tens of thousands, most of them in Asia. It is not easy to know if someone is enlightened.
There are people I've met before whom I thought were enlightened, but later on when I learned more about it I realized that they were instead Dark Night Yogis, people who got as far as the Dark Night but then stopped progressing. Their abilities were impressive but they were perpetually dealing with personal problems and letting those affect them.
There is rhythm and arc to the spiritual path, you need to master this before it's useful to call you enlightened. The enlightened move smoothly through the various stages, and you can easily recognize different states. Maybe not immediately, experience does still remain mysterious, but quickly enough.
Enlightenment is the mastery of the spiritual process. Since the spiritual process is intensely personal, you can only read signs, not see directly.