Enrollment in the state's two-year system hit an all-time high this fall, despite national declines and the state’s aging population. What’s their secret? Central Maine Community College was struck this fall by a rare problem among colleges in the demographically challenged state: it had more students than it could fit on campus. Enrollment at CMCC grew by 22 percent this fall, to 4,121. It was the largest increase in the college’s 60-year history and the first time the total student population exceeded 4,000.