Year	% of cohort
1970	87.9446487426758
1971	77.3014068603516
1972	77.2858276367188
1973	76.2203826904297
1974	79.659049987793
1975	75.3675765991211
1976	81.2869720458984
1977	79.1535034179688
1978	74.1303176879883
1979	74.6546936035156
1980	74.0439682006836
1981	78.9773483276367
1982	76.1834564208984
1983	82.625
1984	79.6671981811523
1985	82.1690902709961
1986	81.6250228881836
1987	73.8419494628906
1988	79.5099029541016
1999	91.5332183837891
2000	88.0820999145508
2001	89.0499877929688
2004	84.9924926757812
2005	86.7311706542969
2006	89.5708694458008
2007	86.9147415161133
2008	88.031867980957
2009	94.7334823608398
2010	93.4519882202148
2013	87.2201080322266