Year | Value | 2022 | 48.039414527013 | 2021 | 48.036329181396 | 2020 | 48.038551878602 | 2019 | 48.033440593503 | 2018 | 48.018339745508 | 2017 | 47.999705512363 | 2016 | 47.980876768638 | 2015 | 47.961281149827 | 2014 | 47.939601147027 | 2013 | 47.914292240489 | 2012 | 47.887757237819 | 2011 | 47.862654039858 | 2010 | 47.838621817602 | 2009 | 47.81935683151 | 2008 | 47.808651430315 | 2007 | 47.804725588242 | 2006 | 47.811311874876 | 2005 | 47.828037540716 | 2004 | 47.849943359007 | 2003 | 47.870165209878 | 2002 | 47.887559625989 | 2001 | 47.904261240256 | 2000 | 47.915520565992 | 1999 | 47.923961702583 | 1998 | 47.935775783703 | 1997 | 47.947579429967 | 1996 | 47.962028941759 | 1995 | 47.98032943797 | 1994 | 47.999212959864 | 1993 | 48.0119584431 | 1992 | 48.015790198929 | 1991 | 48.0079231474 | 1990 | 47.988684690815 | 1989 | 47.955852138383 | 1988 | 47.918484504789 | 1987 | 47.88042008578 | 1986 | 47.840262060732 | 1985 | 47.801747302424 | 1984 | 47.764054032556 | 1983 | 47.724333563537 | 1982 | 47.68260717134 | 1981 | 47.642293323179 | 1980 | 47.603862546263 | 1979 | 47.57095855282 | 1978 | 47.541131904468 | 1977 | 47.506071877321 | 1976 | 47.473897636385 | 1975 | 47.433694438177 | 1974 | 47.37551840151 | 1973 | 47.313290328992 | 1972 | 47.249873349398 | 1971 | 47.187281634098 | 1970 | 47.170951706619 | 1969 | 47.166446590743 | 1968 | 47.126823327996 | 1967 | 47.083034315675 | 1966 | 47.033647617101 | 1965 | 46.975918139663 | 1964 | 46.912082197729 | 1963 | 46.838583123696 | 1962 | 46.757649676758 | 1961 | 46.673160425454 | 1960 | 46.58366437925 |
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