Year	% of cohort
1971	80.4312286376953
1972	80.0924606323242
1974	77.4226303100586
1976	84.5857391357422
1977	84.3573532104492
1978	85.6536026000977
1980	88.386100769043
1985	88.4587326049805
1998	83.4603576660156
1999	83.0590286254883
2005	89.9603805541992
2006	93.7923965454102
2007	90.9720916748047
2008	71.4955368041992
2009	81.2136306762695
2012	75.6502380371094