The findings are part of a major study released this week by Pew Research Centre which surveyed more than 35,000 people about their religious affiliations.

The decline is felt mostly among “mainline Protestants” (with numbers falling by 4.8 percentage points since 2007) and Catholics (down 3.1 percentage points). Evangelical Christians also experienced a dip, but at a slower rate – falling about one percentage point in seven years.

US-based Christian researcher and church statistics expert Ed Stetzer says that the Christian sky isn’t falling: “American Christianity is not dying; but it’s slowly being clarified,” he wrote in a response to the research this week on USA Today. Stetzer writes from an evangelical standpoint, and says that while the statistics suggest mainline Protestantism is “hemorrhaging,” and it’s true that Evangelical denominations are struggling, and some are declining, the statistics paint a better picture for Evangelicalism than is being suggested by news reports.

While mainline Protestants and Catholics appear to be declining as both percentages of the population and in absolute numbers, the evangelical tradition has increased by roughly two million people since 2007[1]. So the number of evangelical Protestants has increased, but so has the number of secular people. The share of evangelical Christians as a percentage of the US population still dropped by 0.9 per cent.

Stetzer argues that the number of people who are “convictional Christians” has remained relatively steady, particularly amongst evangelicals. It’s those with nominal Christian conviction who are shedding the label, and contributing to headlines that suggest Christianity is in sharp decline.

Ross Douthat, for the New York Times also jumped to add qualifiers to the Pew research, pointing out that the “steepest decline is affiliation, not religious practice”. He also suggests that the statistics surrounding the Catholic church might not be quite as critical as a “quick look at Pew” suggests. You can read his response, here.

According to the Pew survey, the number of Americans who say they are unaffiliated with a religion (describing themselves as atheist, agnostic or “nothing in particular”) rose from 16.1 per cent in 2007 to 22.8 per cent in 2014. Non-Christian faiths also saw modest increases, rising 1.2 percentage points (from 4.7 per cent to 5.9 per cent) in the same period. The growth comes mainly from an increase in Muslims and Hindus.

An ageing population would appear a key factor in the decline of Christianity’s numbers. Those claiming no affiliation to religion are young, and getting younger. The median age of unaffiliated adults has dropped to 36 years, down from 38 years in 2007 (the general population median age is 46 for the US). Meanwhile, the median age of mainline Protestants is 52 (up from 50 in 2007) and for Catholics, 49 (up from 45).

36 per cent of young Millennials (aged 18-24) and 34 per cent of older Millennials (aged 25-33) are religiously unaffiliated. That compares with the 16 per cent of all Millennials who identify as Catholic, and 11 per cent as mainline Protestants. One in five are evangelical Protestants.

The survey also suggests that more people are switching out of Christianity than are coming into it. More than 85 per cent of Americans were raised as Christians, but nearly a quarter of those no longer identify with Christianity. “Former Christians”, according to the survey, now represent 19.2 per cent of US adults. 12.9 per cent are former Catholics, while only 2 per cent have converted to Catholicism from another religion.

The only upside in religion-switching for Christianity is that more people have converted to evangelical Christianity than have left it in the survey’s seven year period. 10 per cent of adults identify with evangelical Protestantism, after having been raised in another tradition. That offsets the roughly 8 per cent of adults raised evangelical who have left for another religion, or who no longer identify with organised faith.

The report suggests that a growth in religiously mixed marriages in the United States may be one explanation for the increase in religious unaffiliated Americans. Nearly four in 10 (39 per cent) Americans report being in a religiously mixed marriage, compared to 19 per cent among those who married before 1960. Nearly one in five people surveyed who married since 2010 are either religious unaffiliated respondents who married a Christian spouse, or Christians who married an unaffiliated spouse.

It’s possible that religiously mixed marriages may also contribute to the number of unaffiliated young people in America, as the importance of religion in families is tempered by mixed religious priorities in the household.

You can read the full Pew Research Report here.

[1] The report suggests that once margins of error are taken into account, it is possible that the number of evangelicals may have risen by as many as five million, or remained essentially the same.

Image: LilGoldWmn