Join for FREE,
and start talking with other members, weighing in on community discussions,
Also, by registering and logging in you'll see fewer ads and pesky
welcome messages (like this one!)
Carleton and Colby are closer in size, just around 2000 students, while Grinnell and Swat are both around 1600-1650. Those differences in sizes can affect the raw number of majors.
FWIW, each of these schools happens to be a Keck Consortium member, except Williams (which apparently no longer participates but was one of the founding members).