Year	% of cohort
1971	73.7365570068359
1972	82.0928497314453
1973	81.8163375854492
1974	70.0990905761719
1982	70.2267074584961
1984	78.7812423706055
1985	79.6854019165039
1986	84.0418167114258
1987	84.0103378295898
1988	72.1018676757812
1999	65.5614471435547