Year | Value | 2022 | 50.329389170599 | 2021 | 50.343534884443 | 2020 | 50.35588544637 | 2019 | 50.356931863481 | 2018 | 50.343927248397 | 2017 | 50.33041015545 | 2016 | 50.317324642558 | 2015 | 50.300956233046 | 2014 | 50.281808574791 | 2013 | 50.263370446522 | 2012 | 50.244780182062 | 2011 | 50.22438054761 | 2010 | 50.200954169993 | 2009 | 50.174935914774 | 2008 | 50.148487472353 | 2007 | 50.123699145058 | 2006 | 50.100333986075 | 2005 | 50.079824126668 | 2004 | 50.073523817452 | 2003 | 50.068031476737 | 2002 | 50.049961065554 | 2001 | 50.029317219365 | 2000 | 50.006844825923 | 1999 | 49.984027751431 | 1998 | 49.962343243022 | 1997 | 49.942629002072 | 1996 | 49.925240081213 | 1995 | 49.91051183486 | 1994 | 49.908537857167 | 1993 | 49.918403216334 | 1992 | 49.927226346259 | 1991 | 49.93520311262 | 1990 | 49.941385743264 | 1989 | 49.945436710062 | 1988 | 49.949377313127 | 1987 | 49.952776930004 | 1986 | 49.954509301124 | 1985 | 49.950304626216 | 1984 | 49.940003953748 | 1983 | 49.925794065508 | 1982 | 49.921498604722 | 1981 | 49.926762620829 | 1980 | 49.923576274628 | 1979 | 49.919064198809 | 1978 | 49.920446401656 | 1977 | 49.923955613147 | 1976 | 49.943530588996 | 1975 | 49.976545894522 | 1974 | 50.008841948499 | 1973 | 50.043433826667 | 1972 | 50.077337611226 | 1971 | 50.087597992001 | 1970 | 50.072935995775 | 1969 | 50.056590778963 | 1968 | 50.04014126357 | 1967 | 50.02305851519 | 1966 | 50.005859445229 | 1965 | 49.989822057887 | 1964 | 49.9762117481 | 1963 | 49.965961287958 | 1962 | 49.953013992938 | 1961 | 49.937546107907 | 1960 | 49.916243081643 |
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