A couple hundred thousand new Christians and Muslims a day while each day there is about 1000 fewer godless atheists.
Looks like you'll be basing this on the appearance of babies, then. (Here I refer to actual babies, not foetuses - canoe generally elides the difference between the two). The issues with this are obvious. One is that a baby can't be
any religious identity, and only an atheist in the barest, sparest sense of someone who doesn't believe that gods exist. (In this context sometimes called
implicit atheism). A baby can, at most, ever only be the child of parents who might happen to be religious. A religious identity pertains to the parents, not the baby.
A second issue is that even by the time an individual reaches the stage at which it makes sense that they have sufficient understanding of the concepts involved to regard them as a religious individual, the point is -
do they remain one? The evidence coming from (especially, but very far from exclusively) the United States over the past decade and a half or so says that increasingly they do not.
Daily Mail types who chew their fingernails down to the knuckle about what they perceive to be the number of "Muslim babies" born in the UK lump the two categories together and still manage to get both wrong.
Oh and it doesn't help that western secularism is losing it's influence around the world. That's definitely the cherry on top!
(1) What's the difference between "Western secularism" and "secularism"?
(2) Evidence for this assertion?