Year	% of cohort
1999	98.0297698974609
2000	98.4243774414062
2001	98.586669921875
2002	97.2747421264648
2003	98.2508773803711
2004	98.1656875610352
2005	99.5331726074219
2006	97.9230117797852
2007	98.8117294311523
2008	99.3840713500977
2009	98.506950378418
2010	99.1250762939453
2011	99.1269683837891
2012	99.001953125
2013	99.1931610107422
2014	99.3626937866211
2015	99.4696273803711
2016	99.4170913696289
2017	99.4293670654297
2018	99.508918762207
2019	99.5872192382812
2020	99.4046173095703