Year	% of cohort
1971	97.1511993408203
1972	95.9872436523438
1973	95.8794403076172
1974	96.4554672241211
1975	98.5287628173828
1976	99.1138687133789
1978	99.5791625976562
1979	98.8039779663086
1980	98.497673034668
1981	97.9999923706055
1982	97.8166198730469
1983	98.4642181396484
1987	99.1312026977539
1988	99.4037475585938
1989	99.582893371582
1990	99.2857131958008
1991	99.5122375488281
1999	98.53515625
2000	98.8357620239258
2001	98.6879577636719
2002	99.1276321411133
2003	98.6266708374023
2004	99.1021575927734
2005	98.4985809326172
2006	99.3941421508789
2007	99.5779113769531
2008	98.7656478881836
2009	99.2860336303711
2010	95.5904235839844
2012	99.540771484375
2013	99.4153289794922
2018	99.6165771484375
2019	99.5787734985352
2020	99.9218673706055
2021	99.7413864135742