Didgist said:
We will now mention the item that only the Ultimate Champion of the World could possibly acquire, “Maat's Cap.” As you undoubtedly already know, the only way to get one's hands on this enigmatic item is to level up 15 jobs to level 66 or higher and defeat Maat in single combat with each job. The number of adventurers across all worlds who have taken on this treacherous path and successfully become Maat's successor is a staggering 6,575 characters!
Maat's Cap adds +7 to each statistic as a reward for the grueling work put into its acquisition. When Maat's Cap was first being designed, in order to make it the ultimate status-enhancing piece of equipment, it was given STR+7 to surpass even the wyvern helm +1.
[ Maat's Cap Acquisition ] *All Worlds
Number Acquired
6575
-Vana Census 2008
You have to remember, everyone who has a cap hasn't been registered and verified with this site. Some people who have been registered jumped servers and registered again. Some people have quit some people have been banned. Only SE could give you the true numbers and I'd be willing to bet 6.5k isn't unreasonable.