Even those who are fully engage in the disfellowshipping work don't agree with the Watchtower. So what hope has some poor analyst got to extrapolate information from a dataset where the figures don't mean much? Watchtower keeps having new light. They can reinvent themselves to attract more followers.
But Jesus did say:-
(Matthew 7:13-14) . . .“Go in through the narrow gate; because broad and spacious is the road leading off into destruction, and many are the ones going in through it; 14 whereas narrow is the gate and cramped the road leading off into life, and few are the ones finding it.