Year % 1971 88.18455 1972 94.16545 1973 95.19124 1974 94.37381 1975 95.69829 1976 95.07193 1977 95.73913 1978 95.74843 1979 94.88461 1980 94.47803 1981 95.08692 1982 94.14974 1986 96.70142 1987 100 1988 94.28283 1992 97.42152 1993 97.90785 1999 98.49405 2002 97.73181 2003 99.66023 2004 98.0445 2005 98.61098 2006 100 2007 100 2010 99.17815 2013 97.63998 2016 98.81545 2017 97.73706