Year % 1971 95.94871 1972 91.05839 1973 93.04739 1977 96.72037 1979 94.88592 1980 98.8865 1981 100 1982 100 1983 100 1991 95.54939 1992 93.23713 1995 98.21799 1996 97.5863 1999 69.00006 2007 93.62972 2008 93.90416 2009 95.20744