Year	% of cohort
1972	98.0211868286133
1973	98.7593078613281
1974	96.9936676025391
1976	55.6975288391113
1979	98.3828735351562
1981	97.181999206543
1982	94.2245864868164
1983	91.7813262939453
1984	92.8269805908203
1985	90.7087097167969
1986	90.5377883911133
1994	83.0196228027344
1996	94.2384185791016
1998	91.3126220703125
1999	92.9341812133789
2000	95.1297378540039
2001	98.9990386962891
2002	96.1537322998047
2003	97.8905715942383
2009	96.0156784057617
2011	93.0248413085938
2012	95.40576171875
2015	96.5954284667969
2016	98.5272598266602
2018	84.725830078125
2020	80.3075103759766