Year	% of cohort
2001	99.7519226074219
2002	99.706428527832
2003	99.3317031860352
2004	99.7168197631836
2005	99.7696762084961
2007	99.7753219604492
2008	100
2010	99.3330230712891
2011	100
2012	100
2013	99.7292785644531
2014	99.8091125488281
2015	99.4775390625
2016	99.6679992675781
2017	99.8516082763672
2018	99.460563659668
2019	100
2020	100