On the whole...Christian countries don't force their citizens to be Christian: 10% of Christian countries compared to 78% of Muslim countries. People should have choices. Any religion or no religion. Nobody even asks what religion you are or cares in many countries...That is UNLESS another tries to force their religion down your throat. THEN you are likely to be told by the majority that they aren't interested in religion.
If preachers come to doorsteps, they will either be politely told their not interested or...Have the door firmly shut in their faces!
People who aren't free to freely choose what religion they are, cannot be included in the followers stats....
An example: It has been shown that there are increasing numbers in Arab countries that don't believe.