Do Catholics not read or is it comprehension that causes problems? Did you not see the and maintained in that quote?
And how exactly does a Catholic moving somewhere "maintain" the number of global Catholics? If you move from one state to another does that impact the total number of Protestants, or whatever, that there are in the world? It doesn't change it, or maintain it. It does nothing but put one of a number in a different place.
What? Are we in kindergarten here?