Year	% of cohort
1993	99.8474731445312
1994	99.6934967041016
1995	99.7598190307617
1996	99.6590881347656
1999	99.4241790771484
2000	99.6780395507812
2001	99.1993103027344
2002	99.0549621582031
2003	99.3512191772461
2004	99.3466415405273
2005	98.4170608520508
2006	97.9865112304688
2007	96.0884628295898
2009	96.7848281860352
2010	96.9556274414062
2012	96.264518737793