Year	% of cohort
1995	99.9677886962891
1996	99.8285903930664
1999	98.0856323242188
2000	99.2699279785156
2001	98.0753402709961
2002	98.1922836303711
2003	98.279899597168
2004	96.7452011108398
2006	98.3753967285156
2011	98.6920623779297
2012	98.8023376464844
2015	98.2970962524414
2018	95.7363433837891
2019	99.33203125
2020	98.5826416015625
2021	99.6115798950195