The world's religious landscape is undergoing a major restructuring, as the population becomes increasingly religious and Muslim, according to recent studies.

The percentage of people who identify as non-religious is expected to fall from 16 percent in 2015 to 13 percent in 2060, the Pew Research Center reports . These "religious nones," which include atheists, agnostics and those who do not identify with any particular religion, tend to be older and have fewer children than those who are religious. As a result, their death rates will begin to exceed their birth rates, the study explains.

Though the Christian population will still be slightly larger than the Muslim population, the Muslim population will see many more births. (Pew Research Center)

Among religious people, the number of babies born to Muslims is expected to surpass those born to Christians between 2030 and 2035. The trend is driven by high death rates for Christian populations in some regions, combined with extremely high fertility rates among Muslims.

In the U.S. alone, the Christian population decreased by nearly 8 percent between 2007 and 2014. Over that same time period, the Muslim population showed a slight increase.

But unlike the global projections, the U.S. has seen, and will continue to see, a rise of the "religious none." A larger portion of the nation's population describes themselves as religiously unaffiliated, jumping up 7 percent from 2007 to 2014. And unlike other countries, religiously unaffiliated people in the U.S. tend to be younger than those who belong to a religious group.

Since the majority of "religious nones" live in Asia, the growing lack of religion in the U.S. doesn't carry enough weight to sway the global trend.

Many of the nation's "religious nones" live in New England. Only one in three Massachusetts and New Hampshire residents put themselves in the "highly religious" category and about one in three say they are religiously unaffiliated.

Less than one in six Massachusetts residents say they are Christian, but the state has a larger portion of non-Christian faiths, including a 3 percent Jewish and 1 percent Muslim population.

New England has the lowest percentage of "highly religious" adults. (Pew Research Center)

Alabama and Mississippi, on the other hand, hold the most religious populations. More than three in four people in both states say they are "highly religious," according to Pew.