Table:
text: New England Football Conference
Former members
Former members
Institution Location_ Founded Type_ Enrollment Nickname Joined Left_ Football_Conference Primary_Conference
University of Massachusetts Dartmouth Dartmouth, Massachusetts 1895 Public 7451 Corsairs 1988 2013 Little East (LEC) Little East (LEC)
Massachusetts Maritime Academy Buzzards Bay, Massachusetts 1891 Public 1130 Buccaneers 1972 2013 MASCAC MASCAC
New England College Henniker, New Hampshire 1946 Private 1460 Pilgrims 1971 1973 no longer sponsors football NAC
University of New Haven West Haven, Connecticut 1920 Private 6000 Chargers 1973 1982 Northeast-10 Northeast-10
Plymouth State University Plymouth, New Hampshire 1871 Public 6600 Panthers 1971 1989 1991 2013 MASCAC Little East (LEC)
Western Connecticut State University Danbury, Connecticut 1903 Public 6001 Colonials 1979 1986 MASCAC Little East (LEC)
Westfield State University Westfield, Massachusetts 1838 Public 5166 Owls 1982 2013 MASCAC MASCAC

text: New England Football Conference
Former members
Former members
Institution Location_ Founded Type_ Enrollment Nickname Joined Left_ Football_Conference Primary_Conference
Boston State College Boston, Massachusetts 1872 Public N/A Beacons 1972 1982 Merged into the University of Massachusetts Boston Merged into the University of Massachusetts Boston
Bridgewater State University Bridgewater, Massachusetts 1840 Public 12127 Bears 1965 2013 MASCAC MASCAC
Fitchburg State University Fitchburg, Massachusetts 1894 Public 5201 Falcons 1985 2013 MASCAC MASCAC
Framingham State University Framingham, Massachusetts 1839 Public 5989 Rams 1973 2013 MASCAC MASCAC
University of Massachusetts Boston South Boston, Massachusetts 1964 Public 15741 Beacons 1988 2001 no longer sponsors football Little East (LEC)

Question: When did the institution that retired in 2013 and nicknamed the Corsairs join the former members of the New England Football Conference?