Year | Value | 2021 | 77.099467704343 | 2020 | 77.316408307203 | 2019 | 78.329695455424 | 2018 | 78.106999834592 | 2017 | 78.018426120686 | 2016 | 77.940626682082 | 2015 | 77.795093711405 | 2014 | 77.891942183967 | 2013 | 77.627273855104 | 2012 | 77.424275052713 | 2011 | 77.240573545269 | 2010 | 76.95458220276 | 2009 | 76.697519036722 | 2008 | 76.334145498172 | 2007 | 76.143566962793 | 2006 | 75.872555210102 | 2005 | 75.524625742103 | 2004 | 75.4190516617 | 2003 | 74.969343729303 | 2002 | 74.829093155572 | 2001 | 74.642757945769 | 2000 | 74.313598808017 | 1999 | 74.004873993331 | 1998 | 73.852553479209 | 1997 | 73.598853234034 | 1996 | 73.203702028454 | 1995 | 72.744135734368 | 1994 | 72.691177777285 | 1993 | 72.382886920369 | 1992 | 72.325058758424 | 1991 | 72.246935126237 | 1990 | 72.12377464673 | 1989 | 72.050431292133 | 1988 | 71.829596950021 | 1987 | 71.718560664898 | 1986 | 71.431281142502 | 1985 | 71.072230083897 | 1984 | 70.919691902155 | 1983 | 70.666825708557 | 1982 | 70.55115881854 | 1981 | 70.212368053433 | 1980 | 69.867214480834 | 1979 | 69.788037031273 | 1978 | 69.500939650145 | 1977 | 69.376650859326 | 1976 | 69.040831195973 | 1975 | 68.765084516743 | 1974 | 68.513756715613 | 1973 | 68.159819502305 | 1972 | 67.997470838019 | 1971 | 67.816650298174 | 1970 | 67.534666530693 | 1969 | 67.254502988159 | 1968 | 67.130717216479 | 1967 | 67.415512854896 | 1966 | 67.160987126177 | 1965 | 66.99241598816 | 1964 | 66.948004688292 | 1963 | 66.5299454765 | 1962 | 66.405006087298 | 1961 | 66.488371723493 | 1960 | 66.096975619283 |
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