Year	% of cohort
1977	91.3892974853516
1979	82.3108215332031
1986	87.1465606689453
1987	75.2836685180664
1988	69.6030197143555
1989	57.1882019042969
1990	75.1704864501953
1991	74.7280426025391
1992	75.3731384277344
1993	71.8823623657227
1994	65.7362289428711
1995	62.7235908508301
1996	63.9650611877441
1997	65.0240097045898
1998	66.4329071044922
2001	54.7136688232422
2004	52.8773307800293
2005	57.4172897338867
2006	63.7351684570312
2008	81.8775634765625
2012	75.3113021850586
2016	70.6646423339844