(Thanks, Arlene, for pointing out this page.) USDAA indicates that there are 4,350 "All-breed" (All-Americans or Mixed-breed) dogs registered with them. That presumably covers all dogs living and dead who have ever registered with USDAA, so no way to know how many are currently competing. (So Remington, Jake, and Tika are all listed as "All-breed" dogs.)
Of those, a mere 861 have ever completed their novice title (AD) and 268 their Performance novice title (PDI--although there could be overlap with the same set of dogs. Would be interesting to know how much overlap there is...Do I want to try to figure it out? Hmmm...).
Only 205 have ever earned their Master Agility Dog (MAD) title, including Jake and Tika.
Only 50 have ever earned the Tournament Master (TM) title--NOT including Jake but YESSSSS! Tika finished hers last weekend. Only 30 have earned the TM Bronze--which Tika will get as soon as she earns one more Team qualifier. Maybe at the Bay Team September trial. Maybe not.
In comparison, only a really small number have achieved what Jake did:
Sad to note that I pulled Jake from USDAA when he was only 3 Qs away from his Accomplished Jumpers Dog Silver--which only 2 dogs have ever achieved. Oh, well--
On a larger scale, they don't say how many TOTAL dogs are registered. However, they do give stats overall--