Year Percent 1971 65.07804 1972 111.19034 1973 90.87764 1974 107.93217 1975 124.08938 1976 115.3908 1977 111.45572 1978 107.12098 1979 100.67568 1980 91.63814 1981 92.07155 1983 98.94049