@Corbett "Amherst Class of 2016: 432 graduates, including 167 double majors (38.7%), and 3 triple majors (0.7%). So 39.4% with multiple majors under the “open curriculum”. That’s an impressive number.
https://www.amherst.edu/system/files/media/Amherst%20College%20SSR%20Class%20of%202020.pdf
Williams five-year average distribution of majors, 2012-16: “Approximately 44% of students graduate as double majors”, under a traditional curriculum with distribution requirements. Granted, no mention of triple majors. But otherwise an even higher number.
https://communications.williams.edu/media-relations/fast-facts/"
Williams must be doing something specific in its requirements in order to make dual majoring easier for its students.
I just checked a few of other good LACs. Swarthmore was the closest with about 33% double majors. Middlebury had under 20%. Pomona had 12%. At Carleton it was less than 5%.