|Region||Total pop||Christians||Non-Religious||Religious Non-Christians|
As of 2014, the world has 7.2 billion people. 2.3 billion profess to be Christians. That leaves 4.9 billion non-Christians.
Of the 4.9 billion non-Christians, about 750 million are non-religious - which means the vast majority of non-Christians, 4.15 billion, believe in some kind spiritual reality, but simply don't share the Christian world view.
We need to stop thinking of our world as non-religious. It's not. In fact, the non-religious component is drastically declining. The average annual growth rate of the nonreligious is 0.29% p.a., compared to a global population growth rate of 1.17%. Our world is becoming rapidly more Christian (1.29% AGR), and even more rapidly more Hindu (1.38% AGR) and Islamic (1.81% AGR).
Why do we mainly think of non-Christians as agnostics? One of my colleagues says he strongly suspects the reasons Western Christians are so taken with arguing against atheists include:
1. It's the worldview whose arguments feel like they hit closest to home, because its arguments were mainly formed in reaction against (and scorn of) a biblical worldview.
2. It's the worldview that feels most threatening, because it’s the one (unless I’m mistaken) to which kids raised evangelical who leave the faith tend to embrace more often than other world religions (not counting “vague apathetic humanistic deism, which I’d argue equals practical atheism”).
3. Related to item #1, the atheist worldview is being promoted eloquently by extremely intelligent and eloquent Westerners, which makes it seem more appealing (and thus more threatening) than world religions, which still seem mainly “weird,” because they’re mainly associated with people who are “different” than us.
We should be preparing the next generation to engage other religious worldviews more than worrying about debating with agnostics and atheists--particularly as those with non-Christian religious worldviews (Hindus, Muslims, Jews, Sikhs, Buddhists, etc) migrate to live among us.