And it should be remembered that this graph is only about registered MorphOS 2.x users, not all MorphOS users.
There are many people still using (regularly or occasionally) free 1.x versions.
For example of my closest local friends, who own Pegasos systems, about 40% have registered MorphOS2 while 60% still use 1.x because it's free and they can't afford keyfile or they are waiting with the decision on which platform they'd eventually register it.