Year	% of cohort
2008	99.4309387207031
2009	99.598503112793
2010	98.2982788085938
2011	99.0893020629883
2012	99.5782318115234
2013	99.2866287231445
2014	98.6571273803711
2015	99.5941696166992
2016	99.26611328125
2017	99.8510513305664
2018	99.8636703491211
2019	99.8311462402344
2020	99.9019470214844
2021	99.7673187255859