Year	% of cohort
1971	81.0107574462891
1972	85.4733276367188
1973	84.7092590332031
1974	66.8255004882812
1982	76.6835403442383
1984	86.928596496582
1985	84.1139831542969
1986	88.9237899780273
1987	84.0375518798828
1988	80.6069107055664
1999	67.4455490112305