Year	Percent
1971	99.55163
1972	97.35853
1973	97.64537
1974	96.46378
1975	96.01471
1976	96.40768
1977	95.14114
1978	94.49194
1979	93.63419
1980	94.54886
1981	99.85136
1982	101.74616
1983	100.77681
1984	99.33667
1985	94.88452