Year	% of cohort
2001	98.5970993041992
2002	98.4844665527344
2003	99.2107467651367
2004	99.3141326904297
2005	98.8665771484375
2007	98.4801788330078
2008	97.8867111206055
2010	98.5254821777344
2011	98.0375823974609
2012	98.3284225463867
2013	98.7806015014648
2014	97.9508209228516
2015	99.0815277099609
2016	97.9103088378906
2017	98.2612609863281
2018	98.5921478271484
2019	98.1890869140625
2020	97.593879699707