Year | Value | 2021 | 68.83243331786 | 2020 | 68.936222889243 | 2019 | 69.906965764232 | 2018 | 69.609396205103 | 2017 | 69.333659752573 | 2016 | 68.864613464745 | 2015 | 68.806467683485 | 2014 | 68.453604044575 | 2013 | 68.169050257585 | 2012 | 68.198192094291 | 2011 | 68.35467226009 | 2010 | 68.143411857578 | 2009 | 67.901722685873 | 2008 | 67.301760048628 | 2007 | 66.822952423115 | 2006 | 66.451363970705 | 2005 | 66.075244573627 | 2004 | 65.838181011733 | 2003 | 65.888673409437 | 2002 | 66.059598110408 | 2001 | 65.768199913822 | 2000 | 65.425386808753 | 1999 | 65.077356563894 | 1998 | 63.881163515724 | 1997 | 64.090316933441 | 1996 | 63.837930946738 | 1995 | 63.426871979957 | 1994 | 63.710551996309 | 1993 | 62.576984898728 | 1992 | 61.598681898235 | 1991 | 61.257148497659 | 1990 | 60.834494771451 | 1989 | 60.416853627454 | 1988 | 58.241678758539 | 1987 | 58.934014315196 | 1986 | 58.94597886523 | 1985 | 58.08393924989 | 1984 | 57.34073661471 | 1983 | 56.646046678761 | 1982 | 55.920427012761 | 1981 | 55.678317980666 | 1980 | 55.417264916809 | 1979 | 55.180316551808 | 1978 | 54.479259433185 | 1977 | 53.736279186733 | 1976 | 52.377482046764 | 1975 | 51.956179337351 | 1974 | 51.549527878965 | 1973 | 50.848307725302 | 1972 | 50.26710897864 | 1971 | 49.68273162991 | 1970 | 48.704136471305 | 1969 | 48.163572836584 | 1968 | 47.837255834591 | 1967 | 47.251045233093 | 1966 | 46.856743273323 | 1965 | 46.684580442661 | 1964 | 46.368619105265 | 1963 | 45.393476851507 | 1962 | 44.409726325452 | 1961 | 44.010206163981 | 1960 | 43.325090725529 |
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