What does it say when fewer than 50% of the people in America belong to a church?

What does it say when fewer than 50% of the people in America belong to a church?

The headline in Christianity Today is shocking: Gallup: Fewer Than Half of Americans Belong to a Church. How can that be when somewhere between 70-80% of the population claims to have some religious affiliation? Ultimately, what does istsay when fewer than 50% of the people in America belong to a church?