Year	% of cohort
2008	98.0353775024414
2009	99.5830383300781
2010	99.2425918579102
2011	98.9995422363281
2012	98.3153610229492
2013	98.3265609741211
2014	98.3761825561523
2015	98.5387573242188
2016	94.5003662109375
2017	99.6441116333008
2018	99.4494018554688