Year	% of cohort
1976	74.7878189086914
1977	66.4379806518555
1980	55.0595893859863
1981	55.2247200012207
1982	59.9179992675781
1983	52.5417404174805
1984	48.7769317626953
1985	53.770191192627
1986	56.5904808044434
1987	57.8627090454102
1988	60.8772583007812
1989	56.3909606933594
1990	75.3338623046875
1991	58.7934188842773
1992	79.8901977539062
1993	79.9800415039062
2003	81.2943420410156
2004	75.934700012207
2005	79.217887878418
2006	81.853759765625
2007	69.7023086547852
2008	68.5702667236328
2009	68.5786514282227
2011	59.5122604370117
2012	66.1231079101562
2013	66.5953826904297