The public university at which I teach has an ethnically and religiously diverse student body. Accurate figures are hard to come by because the university doesn’t officially collect the data, but probably about half the undergraduates are Catholic, one-quarter Protestant, and perhaps 5 percent Muslim and 5 percent Jewish. This variety makes for interesting classes.
In my classes on Catholic thought I usually have a preponderance of Catholic students, but also there are always serious Protestants of various stripes—one or two of whom are there to gather intelligence about what’s really wrong with Catholicism (they’re sure that something is but often not quite sure what)—and, more and more often, serious Muslims. These last are in some ways the best thing about the classes.