Year | Value | 2022 | 50.71989275985 | 2021 | 50.743456145145 | 2020 | 50.768651484936 | 2019 | 50.788840881656 | 2018 | 50.804658474261 | 2017 | 50.819483448891 | 2016 | 50.8307469302 | 2015 | 50.838180768746 | 2014 | 50.843364748574 | 2013 | 50.846722965348 | 2012 | 50.848268041793 | 2011 | 50.848222830258 | 2010 | 50.848137372889 | 2009 | 50.847489940118 | 2008 | 50.844680015357 | 2007 | 50.840240709403 | 2006 | 50.83486770079 | 2005 | 50.828574267903 | 2004 | 50.821904827738 | 2003 | 50.815455467201 | 2002 | 50.808903775342 | 2001 | 50.801653234985 | 2000 | 50.791026043991 | 1999 | 50.779005379087 | 1998 | 50.770650845208 | 1997 | 50.762150574443 | 1996 | 50.751428845163 | 1995 | 50.740179848349 | 1994 | 50.728629396869 | 1993 | 50.716999128351 | 1992 | 50.704001005727 | 1991 | 50.688669310919 | 1990 | 50.673362943986 | 1989 | 50.659360947572 | 1988 | 50.647937150784 | 1987 | 50.638570618037 | 1986 | 50.630851912715 | 1985 | 50.626200216222 | 1984 | 50.624176760555 | 1983 | 50.624658388101 | 1982 | 50.625623890755 | 1981 | 50.626893247803 | 1980 | 50.630635086696 | 1979 | 50.639840067325 | 1978 | 50.650963796678 | 1977 | 50.659579960766 | 1976 | 50.66868482452 | 1975 | 50.679780365991 | 1974 | 50.687226308623 | 1973 | 50.687804867827 | 1972 | 50.686592310146 | 1971 | 50.684444847784 | 1970 | 50.683254389812 | 1969 | 50.686750756742 | 1968 | 50.693805776081 | 1967 | 50.703371508081 | 1966 | 50.715527165866 | 1965 | 50.734066738943 | 1964 | 50.754911230629 | 1963 | 50.771507044766 | 1962 | 50.789604415465 | 1961 | 50.81633778306 | 1960 | 50.851880750903 |
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