Of course, even without falsifying numbers, articles in the Watchtower are going to drive those numbers up or down too.
Nobody "knows" they're of the annointed 144,000 because there's no such thing. It's all in their minds. But the Society knows all to well how to maniuplate that.
If they want the numbers to go down, they publish articles saying "It's REALLY unlikely that you're one of the annointed because....".
If they want the numbers to go up, they publish articles like the ones above saying in essence, we may have been wrong about 1935, so it's possible you could be one of the annointed. Those with delusions of granduer will use that information to see what they want to see in themselves.