Year | Value | 2022 | 47.225399842857 | 2021 | 47.176937299399 | 2020 | 47.109831841002 | 2019 | 47.078841310959 | 2018 | 47.119914838715 | 2017 | 47.173283959264 | 2016 | 47.241850361027 | 2015 | 47.327006554697 | 2014 | 47.428124056601 | 2013 | 47.546788794645 | 2012 | 47.680783756522 | 2011 | 47.829874155591 | 2010 | 47.947235510596 | 2009 | 48.029483963568 | 2008 | 48.125121234689 | 2007 | 48.237273058787 | 2006 | 48.369151044048 | 2005 | 48.521728269995 | 2004 | 48.693721221509 | 2003 | 48.882143549104 | 2002 | 49.083627828647 | 2001 | 49.297482169422 | 2000 | 49.524144606315 | 1999 | 49.724668678791 | 1998 | 49.892017899621 | 1997 | 50.060604058986 | 1996 | 50.226495220341 | 1995 | 50.38770196526 | 1994 | 50.544267322479 | 1993 | 50.634519717974 | 1992 | 50.657246466428 | 1991 | 50.680338285639 | 1990 | 50.705511127722 | 1989 | 50.73101110566 | 1988 | 50.757552938341 | 1987 | 50.787305705103 | 1986 | 50.822350204895 | 1985 | 50.863816438016 | 1984 | 50.915236246316 | 1983 | 50.975518494762 | 1982 | 51.020931713018 | 1981 | 51.046640848628 | 1980 | 51.072355217002 | 1979 | 51.058136351191 | 1978 | 51.024122628901 | 1977 | 51.01095523939 | 1976 | 50.943115942029 | 1975 | 50.85539182806 | 1974 | 50.81636024477 | 1973 | 50.805569535313 | 1972 | 50.806256181188 | 1971 | 50.780568805457 | 1970 | 50.700257134294 | 1969 | 50.590880864116 | 1968 | 50.547213192738 | 1967 | 50.584031079144 | 1966 | 50.633960937526 | 1965 | 50.682010779296 | 1964 | 50.725977317104 | 1963 | 50.764969012572 | 1962 | 50.800389203215 | 1961 | 50.829342109129 | 1960 | 50.848135971064 |
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