The Current workforce in this country is not going back to school because its to expensive, this is a simple fact. Ask the parents at a open house. Your 18-26 somethings rather work in a clothing store soon to be closed by a amazon warehouse... then go to school and study something that might be challenging.
https://nscresearchcenter.org/currenttermenrollmentestimate-spring2017/
https://nscresearchcenter.org/wp-content/uploads/CurrentTermEnrollment-Spring2017.pdf
If you want to increase enrollment (student body / numbers) at all campuses you need to drop the cost of tuition. This is as simple as supply and demand.