Year	% of cohort
1991	65.5655136108398
1993	84.1607284545898
1997	88.6024932861328
1998	87.1190719604492
1999	93.0875396728516
2002	89.6479873657227
2003	84.1557998657227
2004	87.9685363769531
2005	89.6576766967773
2008	92.6899185180664
2009	93.9515914916992
2012	96.9278411865234
2017	93.509880065918
