Year % 1971 75.73831 1972 69.89795 1973 76.28981 1974 85.80794 1975 97.81659 1976 78.90214 1977 86.5834 1979 83.0115 1982 67.12119 1984 83.62666 1985 78.04834 1986 73.07652 1987 70.85989 1988 71.43307 1999 77.2827