These charts were all made from surveys done by the UCLA Higher Education Research Institute. Since 1971, they have been surveying incoming college freshmen on a variety of subjects -- and one of those subjects is religion. Note that since 1971 the percentage of those without religion has nearly doubled. The number of non-religious freshmen has grown by 12.1 points (11.9 points among women and 12.7 among men).
This can't be ascribed to the effect of a college education. This is the view of incoming freshmen, which means these are the views they had when they entered their college. Much of this increase is the growing disenchantment of young people with their church or religion in general (especially the racism, misogyny, and homophobia demonstrated in many churches).
But there is another factor contributing to the rise in the number of non-religious young people -- a rise in the number of young people who grew up with non-religious parents. Note in the chart below that the number of non-religious parents, while not as large as the non-religious young people, has also shown a significant growth (10.7 points among mothers and 12.6 points among fathers).
I can think of no reason why these trends won't continue in future decades -- resulting in an even greater percentage of the population abandoning religion for reason.
And lest you think this is a trend that is only happening in secular colleges, look at the chart below. The number of students entering both catholic and other religious colleges that are non-religious has also grown significantly -- and the growth shown has occurred just in the last decade (with a 4.3 point rise in catholic schools and a whopping 8.1 point rise in other religious schools.
