Year	% of cohort
1971	86.9061889648438
1974	87.556640625
1975	88.8377685546875
1976	90.5382308959961
1977	94.6801300048828
1978	94.9125671386719
1979	94.4887771606445
1985	99.5
1986	94.9095306396484
1987	94.6691207885742
1988	95.1795501708984
1989	96.45556640625
1990	96.6000518798828
1991	96.3792266845703
1999	97.9584808349609