The Story: A new survey finds America’s religious makeup has shifted dramatically in the past 15 years, with a sharp drop in the number of Americans who say they’re members of a Protestant denomination.

The Background: Fifteen years ago, half of all Americans identified as Protestant. But a new survey by ABC News/The Washington Post finds that number has decreased to the point where a little more than one-in-three claim to be a Protestant Christian.

Among all Protestants, a little more than half (56 percent) currently say they’re “evangelical or born-again.” While that percentage has remained steady since 2003, the declines in the number who say they’re either evangelical or non-evangelical Protestants are roughly equal, down seven and six points, respectively.

The decline has occurred disproportionately among whites, notes ABC News. Thirty-nine percent of whites now identify as members of a Protestant denomination, down 13 points since 2003. That compares with an eight-point decline among Hispanics (from 22 percent to 14 percent) and just three points among blacks (from 64 percent to 61 percent). (An additional factor is the shrinking white non-Hispanic population, from 69 percent of all Americans in 2000 to an estimated 61 percent in 2016, according to the U.S. Census Bureau.)

The number of Catholics, “other Christians,” and “other religions” has remained the same or changed by less than 3 percent. The majority of the decline comes from the number of Protestants who now express no religious affiliation. The religiously unaffiliated—sometimes referred to as “nones”—have risen from 12 percent of all American adults in 2003 to 21 percent in 2017.

The largest shifts to the “none” category, according to the survey, are a 16-point increase among young adults (age 18 to 29) and political liberals. The smallest changes have occurred among Republicans, conservatives, and blacks (+4 points in each group) as well as older Americans (+5 points).

Having no religious affiliation is most prevalent among the young. In the range of 18- to 29-year-olds, 35 percent are religiously unaffiliated compared to 13 percent among those age 50 and older. The percentage of nones is also higher among men than women (25 percent vs. 17 percent), among college graduates vs. those without a degree (25 percent vs. 20 percent), and among whites and Hispanics than among blacks (22 percent and 20 percent vs. 15 percent).

Thirty-five percent of liberals report no religious affiliation, compared with 21 percent of moderates and 12 percent of conservatives. About one-in-four Democrats (23 percent) and independents (25 percent) don’t report a religion, compared to just one-in-ten (10 percent) for Republicans.

What It Means: In 1971, only 5 percent of Americans claimed no religious affiliation. In fact, until 1993 the nones never composed more than 8 percent of the population. But something has changed to cause a rapid increase in the abandonment of religion.

“The growing ranks of religiously unaffiliated Americans have been fed by striking simultaneous losses among white Christian groups,” says Robert P. Jones, PRRI CEO and author of The End of White Christian America. “The religiously unaffiliated now outnumber Catholics, white mainline Protestants, and white evangelical Protestants, and their growth has been a key factor in the transformation of the country over the last decade from a majority white Christian nation to a minority white Christian nation.”

What are we to make of this decline? Perhaps we should rejoice.

“The big trends are clear,” Ed Stetzer said in 2015, “the nominals are becoming the nones, yet the convictional are remaining committed.”

“In other words, Americans whose Christianity was nominal—in name only—are casting aside the name,” Stetzer added. “They are now aligning publicly with what they’ve actually not believed all along. The percentage of convictional Christians remains rather steady, but because the nominal Christians now are unaffiliated the overall percentage of self-identified Christians is decline. This overall decline is what [a Pew research survey] shows—and I expect it to accelerate.”

Stetzer was right—the decline in nominal Christians has indeed accelerated over the past three years.

What this means is not that America has become “post-Christian” but rather that society is now, as Russell Moore has said, in a “post-pretend-Christian” state.

“If we take the opportunity to be the church, we may find that America is not ‘post-Christian,’ but is instead maybe ‘pre-Christian,’” Moore says. “It may be that this land is filled with people who, though often Christ-haunted, have never known the power of the gospel, yet.”

This decline of nominal Protestantism may be good news if we see it as an opportunity to share the Good News with those who didn’t realize what they abandoned.