I doubt AmEx publishes this information, but does any source publish estimates of the number of green cards, gold cards, etc.? I read an article recently that states that approximately 1% of platinum cardholders get Centurion invites, and that only 1% of total cardholders are platinums!

I know at an online forum like this it seems like everyone and their brother has top-tier everything, but what do the numbers really show?