Year	% of cohort
1971	35.8671798706055
1972	51.2682113647461
1973	46.8245315551758
1975	56.9602890014648
1976	57.355110168457
1977	50.1754913330078
1980	44.0637283325195
1981	58.8499984741211
1982	55.4916801452637
1985	50.3860397338867
1986	26.2865104675293
1987	67.020622253418
1988	60.5131988525391
1990	36.0852584838867
1991	24.1340293884277
2008	53.5921897888184
2009	56.2672080993652
2010	54.9530906677246
2011	56.699520111084