For purposes of defraying the expenses of the association, the member institutions shall pay the necessary expenses incurred by the members and shall appropriate annually such sums for dues as may be assessed by the association. The assessment shall be made only upon a two-thirds vote of the membership present at the meeting, after notice of the taking of that vote shall have been given to each member institution in writing at least 60 days before the meeting of the association. Dues shall be assessed upon a graduated scale according to the size of each member institution.
N.J.S. § 18A:64-51