With the highest median age of any state, Maine has seen an estimated 10 percent decline over the last 10 years in its number of new high school graduates — precisely the people Richards needs. New students checking in at freshman orientation at the University of Maine get nametags are color-coded to show which state they came from among those where the university aggressively recruits. Yet UMaine has managed to increase its undergraduate enrollment during that period by about 5 percent. And the state’s community colleges, which depend on the same dwindling supply of learners, are reporting record numbers of applications for the fall.