Year	Number
1961	0.6956521739130435
1962	0.6808510638297872
1963	0.6666666666666667
1964	0.673469387755102
1965	0.66
1966	0.6796116504854369
1967	0.6728971962616822
1968	0.6727272727272727
1969	0.6440677966101694
1970	0.65
1971	0.64
1972	0.640625
1973	0.6461538461538461
1974	0.6466165413533834
1975	0.6423357664233577
1976	0.6571428571428571
1977	0.6573426573426574
1978	0.6758620689655173
1979	0.6802721088435374
1980	0.7000000000000001
1981	0.7058823529411765
1982	0.7419354838709677
1983	0.7692307692307693
1984	0.7961783439490446
1985	0.8227848101265823
1986	0.8490566037735849
1987	0.8750000000000001
1988	0.9006211180124223
1989	0.9259259259259258
1990	0.9597523219814241
1991	0.9753086419753085
1992	0.9938650306748466
1993	1
1994	0.9941176470588234
1995	0.9608938547486033
1996	0.8974358974358974
1997	0.8476190476190476
1998	0.8088888888888889