Year	Percent
1971	97.96949
1972	95.91841
1973	95.71656
1974	94.58333
1975	94.37259
1976	94.69279
1977	93.76338
1978	92.59317
1979	92.06522
1980	92.79727
1981	97.54097
1982	99.49633
1983	98.8557
1984	97.05544
1985	92.65478