Year	% of cohort
2008	97.9039001464844
2009	99.3759613037109
2010	98.7443695068359
2011	98.8029708862305
2012	98.3882675170898
2013	98.2475814819336
2014	98.4440078735352
2015	98.2194366455078
2016	93.4997863769531
2017	99.6366119384766
2018	99.6817779541016