Year	% of cohort
1986	68.9873733520508
1987	66.5345687866211
1988	67.9372787475586
1989	54.7218894958496
1990	59.0504302978516
1991	69.3462829589844
1993	67.2857131958008
1994	59.223331451416
1995	65.3929672241211
1996	60.0885391235352
1997	65.1921615600586