Year % 1971 72.10982 1972 67.61085 1973 74.00635 1974 83.04826 1975 97.46631 1976 74.37578 1977 83.25935 1979 83.07991 1982 68.36677 1984 94.56623 1985 87.85127 1986 80.06724 1987 76.14889 1988 78.63106 1999 85.44604