Complex sentence: In the 2005--2006 school year, Kempner had a population of 2,616 students: 723 freshmen, 683 sophomores, 597 juniors, and 613 seniors.
Split into simpler sentences: In the 2005-2006 school year, Kempner had a population of 2616 students. This was compromised of 723 freshmen, 683 sophomores, 597 juniors, and 613 seniors.