If current trends continue, Christians could soon become a minority in the US within just a few decades, according to a new report. Social trends like this are notoriously hard to predict, but it's evident that the number of people following Christianity in the US has been slipping since the 1970s – and little seems to be stopping the demise.

In 1972, up to 90 percent of Americans identified as Christian. By 2020, that number had slipped to about 64 percent, while around 30 percent reported being religiously unaffiliated and all other religions – including Judaism, Islam, Hinduism, and Buddhism – accounted for just 6 percent of the population.

A new report by Pew Research has looked to see how this trend might continue under a few different scenarios. There are numerous factors that will influence this future, such as birth rates and migration patterns, but one of the most important is the rates of “religious switching” whereby people no longer identify with the religion they grew up with.

Under the first scenario, where no one in the US changes their religion after 2020, Christianity could claw onto a majority of 54 percent of the population by 2070. Meanwhile, the religiously unaffiliated would remain a substantial minority at 34 percent.

If religious switching among young Americans continued at current rates, Christians would slip below 50 percent of the population by 2060, accounting for 46 percent of the population in 2070. They would still be the largest religious group in the US, however.

Another scenario is that the US will see rising disaffiliation and the rate of switching increases. In this case, the percentage of Christians in the US could fall to between 35 and 39 percent by 2070. The proportion of religiously unaffiliated Americans could rise to around 52 percent. 

The report says that the current projections suggest the US could be following the path taken by many countries in Western Europe in the latter half of the 20th century. In Britain, for example, the number of religiously unaffiliated overtook Christians to become the largest group in 2009, according to the British Social Attitudes Survey.

The report unearthed a number of other interesting insights. As you might expect, moving away from religion tends to be associated with younger people. It’s apparent that people who have become unaffiliated after being raised a Christian are a little more likely to have a college degree than those who remain Christian.

They also found that men are more likely to move away from Christianity in the US, while women are more likely to retain their Christian identity. 

However, the researchers cautioned to add that all of these scenarios are just predictions and, in the real world, many social trends can be largely unforeseeable. 

“Though some scenarios are more plausible than others, the future is uncertain, and it is possible for the religious composition of the United States in 2070 to fall outside the ranges projected,” the report remarks.

“New patterns of religious change could emerge at any time. Armed conflicts, social movements, rising authoritarianism, natural disasters, or worsening economic conditions are just a few of the circumstances that sometimes trigger sudden social – and religious – upheavals,” it notes.