Year	Percent
1971	96.45802
1972	94.54251
1973	93.87378
1974	92.78673
1975	92.80339
1976	93.05346
1977	92.44708
1978	90.77916
1979	90.56556
1980	91.12184
1981	95.32976
1982	97.34347
1983	97.0177
1984	94.87356
1985	90.52308