Year	% of cohort
1997	96.0634307861328
1998	98.4545593261719
1999	98.5719833374023
2000	99.0226593017578
2001	98.3211364746094
2002	98.4427871704102
2003	98.3023300170898
2004	98.5062637329102
2005	97.786018371582
2006	94.4785690307617
2007	99.6700134277344
2008	98.969108581543
2009	98.5637512207031
2010	98.123779296875
2011	98.4384613037109
2012	98.7615509033203
2013	99.2751388549805
2014	98.8167495727539
2015	98.8680725097656
2016	99.1029891967773
2017	99.4620513916016
2018	99.3848495483398
2019	99.0218276977539
2020	99.418571472168