So we take the world population slice that to the MUCH smaller segment of Christians and there you have growth predominantly by birth only and some minor convert action in third world shtholes.
Ah but don't celebrate to fast my sub 80 IQ point drooling moron. Now you have to look at people leaving the faith in record numbers and we see why churches all over are closing their doors forever.
Google up church for sale and enjoy the selection.
You know something, the world population grows by about 1.2% each year. Christianity grows by 1.3%