Year	% of cohort
1982	98.2682723999023
1985	89.9258193969727
1986	88.195182800293
1987	91.9428405761719
1988	96.5178375244141
1991	89.8954696655273
1992	100
1993	99.5484085083008
1994	97.8051986694336
1995	94.2024765014648
1997	97.3461380004883
1998	98.3038482666016
1999	96.0970001220703
2000	97.2265472412109
2001	97.778678894043
2003	99.29833984375
2004	97.2118301391602
2011	96.7967987060547
2015	99.1384963989258
2016	98.2445297241211
2017	96.8470230102539
2018	97.9737930297852