Year | Value | 2021 | 75.99522209966 | 2020 | 76.846656945291 | 2019 | 78.413343660184 | 2018 | 78.16147570593 | 2017 | 78.002164633408 | 2016 | 77.688566960434 | 2015 | 77.404150190439 | 2014 | 77.26083059838 | 2013 | 77.05551822203 | 2012 | 76.665481485367 | 2011 | 76.374543628739 | 2010 | 75.94908127269 | 2009 | 75.728371806565 | 2008 | 75.300524701667 | 2007 | 75.068981387261 | 2006 | 74.670964945263 | 2005 | 74.211635366119 | 2004 | 74.10638721867 | 2003 | 73.744142017878 | 2002 | 73.607593740551 | 2001 | 73.522208779318 | 2000 | 73.37450159251 | 1999 | 73.07586837144 | 1998 | 73.327420029161 | 1997 | 72.970083414687 | 1996 | 72.664092176776 | 1995 | 72.269723697179 | 1994 | 72.306745934635 | 1993 | 72.052485138391 | 1992 | 72.420901997371 | 1991 | 73.136688032938 | 1990 | 73.417814904842 | 1989 | 73.392542478821 | 1988 | 73.164132993612 | 1987 | 73.080364828082 | 1986 | 72.946019635309 | 1985 | 72.293349466575 | 1984 | 72.129156798042 | 1983 | 72.235566876056 | 1982 | 72.214638095107 | 1981 | 71.926563836342 | 1980 | 71.632027418849 | 1979 | 71.491821148984 | 1978 | 71.486448292347 | 1977 | 71.397076063338 | 1976 | 71.23768367858 | 1975 | 71.214124575397 | 1974 | 71.326735332111 | 1973 | 71.076969366467 | 1972 | 70.954888177047 | 1971 | 70.826910127668 | 1970 | 70.529995015677 | 1969 | 69.802040675267 | 1968 | 70.056527432437 | 1967 | 69.81030634112 | 1966 | 69.93182036685 | 1965 | 69.669299481034 | 1964 | 69.6817945084 | 1963 | 69.211446444556 | 1962 | 68.625515986985 | 1961 | 68.783930995492 | 1960 | 68.520134991839 |
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