A&M has 32 as well.
It depends on a number of things. Number of guys that enrolled at semester, those guys count on last years total, medical hardships (that the SEC really has been taking advantage of), new recruits being told sorry we don't have room for you after signing day and uperclassmen that don't play being told thanks for the last 1,2,3 years but you no longer have a full ride.
The B1G has put itself at a disadvantage in recruiting since the late 1950's by not allowing oversigning on a grand scale. And as of last year when many B1G schools started offering 4-year scholarships instead of 1-year scholarships that have to be renewed. While some believe the 4-year scholarship may help, it won't do much to dent the gap with the SEC. And no matter what it's location, location, location, history, tradition,.......... oh and wins.