Year	% of cohort
1971	46.9360618591309
1972	67.4533081054688
1973	65.7265167236328
1982	52.2956695556641
1984	55.0741882324219
1985	62.176139831543
1986	65.7681503295898
1987	74.1912078857422
1988	48.5288200378418
1999	47.1912307739258