Year % of cohort 1977 78.702392578125 1978 73.7964477539062 1979 73.7985000610352 1980 54.9875984191895 1981 74.1008911132812 1982 73.1091690063477 1983 73.0027618408203 1984 72.4959869384766 1985 72.7261505126953 1986 73.3816070556641 2015 99.5249633789062 2016 99.6182174682617 2017 99.7245101928711 2018 99.4950332641602 2019 99.7342529296875 2020 99.6015319824219 2021 99.6883163452148