Tanzania is about 1/3 Muslim, 1/3 Christian (mostly Catholic) and 1/3 African tribal religions.
The area that this parish is split about 50\50 Catholic and African tribal. There is a mosque in the main town, so there are a few muslims, but not many.
When I asked the bishop about why there are so many practioners of the tribal religions, as it seemed so backwards. He said that it was a matter of pragmatism. Those who practice the tribal religions don't want to become Muslim, as they don't want to give up beer, and they don't want to become Catholic, as they want to have more than one wife (it's a status symbol in African society, even among the muslims)
So the opportunity to convert adult males is small. Especially when the bishop tells a prospective convert that not only can he have just one wife, it has to be the first wife, not any wife of his choosing. And he cannot simply dismiss the other wives, but still has to provide for them, but treat them as sisters. That doesn't go over very well.
So his plan is to have the best schools, so that the children come to him, and he can reach them with the Gospel while they are young and before they marry.
Unlike the teens from our parish, who were over there building the church, I was over there setting up computer labs at the bishop's Secondary schools and teaching the teachers.
On the last trip, the trip that involved the consecration, I set up a computer lab at the bishop's minor seminary. I was fortunate to be asked by the bishop to give an address and a guest lecture to the seminarians