How many people are actually religious in the world?

No, you're right. A lot of Christians I know I refer to as "lukewarm" or "name only". This is because they know God and Jesus and the basics, but don't know his word. They also continue sinning despite knowing what is right, something talked about in the Bible. That's the problem with many Christians. They don't practice what they preach or dont' even know what they believe.