What is the ratio of conversion from Christianity to Islam and Islam to Christianity?

Answer 1

It would be impossible to answer this question accurately.

In the first place, groups don't usually keep statistics on whether a convert's former religion was deep and real or just nominal.

In the second place, it is difficult to distinguish between people who have truly converted to a religion and people who simply pretend to change because they want to marry someone or because there are commercial advantages.

In the third place, most Muslim societies make it very difficult for anyone to give up Islam. Many people who do leave Islam for Christianity, Buddhism or just Atheism won't admit to the change out loud.

It is a fact that some Muslims become Christians and some Christians become Muslims, but that is all we can really say.