The unaffiliated segment is growing in the U.S., but worldwide it's a different story. Birth rates have something to do with the world trends.

The Pew Research report says:

The religious profile of the world is rapidly changing, driven primarily by differences in fertility rates and the size of youth populations among the world’s major religions, as well as by people switching faiths. Over the next four decades, Christians will remain the largest religious group, but Islam will grow faster than any other major religion. If current trends continue, by 2050 …

One of the main determinants of that future growth is where each group is geographically concentrated today. Religions with many adherents in developing countries – where birth rates are high, and infant mortality rates generally have been falling – are likely to grow quickly. Much of the worldwide growth of Islam and Christianity, for example, is expected to take place in sub-Saharan Africa. Today’s religiously unaffiliated population, by contrast, is heavily concentrated in places with low fertility and aging populations, such as Europe, North America, China and Japan.

[pewforum.org]

If only I could live long enough...hard to believe from where I sit.

I'll believe it when atheist get elected to us congress.

Great to hear.

That remains to be seen and I for one will believe it after the fact.