Year | Value | 2022 | 51.07176437614 | 2021 | 51.095922729501 | 2020 | 51.106134194456 | 2019 | 51.11623379798 | 2018 | 51.126205728033 | 2017 | 51.136981576486 | 2016 | 51.148857988034 | 2015 | 51.162798289426 | 2014 | 51.178238125131 | 2013 | 51.194697483537 | 2012 | 51.214503234624 | 2011 | 51.237717189704 | 2010 | 51.263337490794 | 2009 | 51.291980607503 | 2008 | 51.323350148546 | 2007 | 51.357162532524 | 2006 | 51.393105405022 | 2005 | 51.432994947004 | 2004 | 51.475142278792 | 2003 | 51.519678415319 | 2002 | 51.56713106753 | 2001 | 51.6170710385 | 2000 | 51.669620306155 | 1999 | 51.699190657135 | 1998 | 51.711279079739 | 1997 | 51.732275532049 | 1996 | 51.757328353222 | 1995 | 51.786166438781 | 1994 | 51.818493573476 | 1993 | 51.855199019447 | 1992 | 51.897556380046 | 1991 | 51.947285837486 | 1990 | 52.003726428336 | 1989 | 52.067967955239 | 1988 | 52.138418782691 | 1987 | 52.220149001474 | 1986 | 52.301528302743 | 1985 | 52.362551324515 | 1984 | 52.410297372654 | 1983 | 52.459016393443 | 1982 | 52.513486513486 | 1981 | 52.569398785082 | 1980 | 52.628943629423 | 1979 | 52.693258217959 | 1978 | 52.768878928288 | 1977 | 52.860163465003 | 1976 | 52.978214639214 | 1975 | 53.09649082905 | 1974 | 53.179984908017 | 1973 | 53.240621788284 | 1972 | 53.285205304713 | 1971 | 53.318214640311 | 1970 | 53.27917700902 | 1969 | 53.206372959459 | 1968 | 53.188634714252 | 1967 | 53.18882424045 | 1966 | 53.190709518114 | 1965 | 53.195154955609 | 1964 | 53.201363060518 | 1963 | 53.205480213815 | 1962 | 53.207038658434 | 1961 | 53.210995759614 | 1960 | 53.211181055156 |
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