Year	% of total
1960	87.50000000000001
1961	90.32258064516128
1962	96.87500000000001
1963	91.1764705882353
1964	93.93939393939394
1965	94.5945945945946
1966	94.73684210526315
1967	95.6521739130435
1968	98
1969	98.27586206896551
1970	98.57142857142857
1971	98.59154929577464
1972	100
1973	100
1974	100
1975	100
1976	100
1977	100
1978	100
1979	100
1980	100
1981	100
1982	100
1983	100
1984	100
1985	100
1986	100
1987	100
1988	100
1989	100