I estimate there were very roughly 50 customers in the end. (I was an EDG engineer and didn't work on admin stuff — so it might be off, but not much. I'm estimating based on support tickets origins.) That's down from maybe double that at our max (again, my estimate). I heard of fairly few customers switching to Clang or other projects (Intel being the most notable exception). Most of our customers we "lost" were due to mergers/acquisitions (i.e., two customers suddenly became just one).