Gakuen Utopia Manabi Straight! (2007)

A group of young high school girls living in the year 2035 while they attend the all-girl Seioh Private High School. Since the birth rate has dropped dramatically, schools are being closed down due to the sheer lack of students available to teach. Morale in schools has dropped dramatically, and Seioh is no exception. (Source: MyAnimeList)