Year	% of cohort
1971	93.3406829833984
1972	94.9490814208984
1973	94.1486129760742
1974	92.4632720947266
1975	97.3358306884766
1976	97.4985427856445
1977	96.9488983154297
1978	97.013427734375
1979	92.8938903808594
1980	98.0271224975586
1981	97.9449005126953
1982	98.8657608032227
1983	99.2205276489258
1984	99.785041809082
1985	98.5292816162109
1986	92.6609802246094
1988	97.5432205200195
1991	99.3184432983398
2004	97.8519592285156
2005	97.5459976196289
2006	97.3644409179688
2010	92.8911590576172
2011	94.4172668457031
2012	90.6846923828125
2013	91.6866912841797
2015	95.966178894043
2016	98.6257934570312
2017	97.9569778442383
2018	99.2624206542969
2019	99.4549865722656
2020	99.4611968994141