In recent years, we've heard countless news stories and reports claiming there is a continuing decline of religion in the United States, but do the numbers really prove that? And if there is significant decline, what caused that change? The data are very closely tied to generational differences, and follow the coming of age of the youngest American adults.

First, we must understand the layout of religion in the U.S. Using data from 2014, roughly 47% of American adults are Protestant, 21% Catholic, 2% Mormon, 2% Jewish, and 1% Muslim. In addition to this, 23% of adults reported having no religious affiliation. When broken down further by age, about 38% of 18-29 year olds are unaffiliated, followed by 26% of 30-49 year olds, 17% of 50-64 year olds, and 12% of those over the age of 65. (These age categories roughly fall into Millennials, Generation X, Baby Boomers, and the Silent Generation, respectively.) Looking at this data set, there is an unmistakable correlation between age and lack of religious affiliation. (I think it would also be interesting to ask unaffiliated adults what religion they grew up with.)

Closely related is how positively or negatively American adults view religious organizations. From 2010 to 2015, the percent of Millennials who reported that religious organizations have a positive impact on our country decreased by 18%, while the three older generations had marginal increases. In looking at these five-year differences, we must account for members of Gen X and the Silent Generation who passed away, as well as the youngest Millennials who came of age in that time period.

Finally, we examine the results of a seven-year study about Americans' general religious beliefs. The percentage of adults who say they believe God exists declined only 3 points to 89% in 2014, however only 63% say they are "absolutely certain" about this belief. According to this study, those who reported having no religion (nicknamed the "nones") has increased to 23%. Once again, of course, we must consider the changing age demographic in the U.S.

While it seems most, if not all, data point to at least a slight decline in religious affiliation in the United States, none wholly agree on the rate at which it is dropping. If it follows the generations, we can only assume religion will continue declining as more young people come of age and more older people pass away. Perhaps we will have more questions than answers for awhile. Will Generation Z be even less religious than Millennials? Is there an ultimate pattern of inclining and declining religion across United States history that will continue, and thus will religion make a comeback a generation or two from now? For now, we can only guess.