Year | Value | 2021 | 53.816453816454 | 2020 | 53.889218889219 | 2019 | 53.959013959014 | 2018 | 54.143154143154 | 2017 | 54.024354024354 | 2016 | 53.905553905554 | 2015 | 54.826254826255 | 2014 | 54.588898783022 | 2013 | 54.841199168893 | 2012 | 54.61743772242 | 2011 | 55.112692763938 | 2010 | 55.508449451527 | 2009 | 56.84553809665 | 2008 | 57.147511848341 | 2007 | 56.706161137441 | 2006 | 56.86018957346 | 2005 | 57.396327014218 | 2004 | 57.742890995261 | 2003 | 56.685426540284 | 2002 | 57.467417061611 | 2001 | 56.95201421801 | 2000 | 58.045023696682 | 1999 | 58.43009478673 | 1998 | 56.747630331753 | 1997 | 58.154620853081 | 1996 | 57.778436018957 | 1995 | 58.196090047393 | 1994 | 57.772511848341 | 1993 | 58.261255924171 | 1992 | 58.169431279621 | 1991 | 58.33827014218 | 1990 | 59.774881516588 | 1989 | 59.416469194313 | 1988 | 59.697867298578 | 1987 | 59.66528436019 | 1986 | 59.774881516588 | 1985 | 59.828199052133 | 1984 | 59.683056872038 | 1983 | 59.502369668246 | 1982 | 60.053317535545 | 1981 | 60.145142180095 | 1980 | 60.343601895735 | 1979 | 60.331753554502 | 1978 | 60.73163507109 | 1977 | 61.190758293839 | 1976 | 61.608412322275 | 1975 | 61.821682464455 | 1974 | 62.177132701422 | 1973 | 62.440758293839 | 1972 | 62.846563981043 | 1971 | 63.281990521327 | 1970 | 65.204383886256 | 1969 | 65.704976303317 | 1968 | 66.193720379147 | 1967 | 66.401066350711 | 1966 | 66.590639810426 | 1965 | 66.566943127962 | 1964 | 66.877962085308 | 1963 | 67.443720379147 | 1962 | 67.751777251185 | 1961 | 68.036137440758 |
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