Year	% of cohort
1971	94.389892578125
1972	96.1936264038086
1973	95.4884414672852
1974	93.7654266357422
1975	97.8833694458008
1976	97.44921875
1977	96.7073974609375
1978	98.0284423828125
1979	94.3243026733398
1980	96.6819000244141
1981	98.8491516113281
1982	98.4804229736328
1983	99.2393493652344
1984	99.7852401733398
1985	98.9466171264648
1986	94.4374618530273
1988	97.5123291015625
1991	99.0846710205078
2004	96.9898300170898
2005	96.4874801635742
2006	97.8080596923828
2010	93.3173675537109
2011	95.2052307128906
2012	91.7062911987305
2013	92.8405227661133
2015	96.2959518432617
2016	98.8599395751953
2017	98.2501220703125
2018	99.5991821289062
2019	99.5609664916992
2020	99.5723190307617