Year | Value | 2022 | 49.833613848465 | 2021 | 49.820623190695 | 2020 | 49.801553026104 | 2019 | 49.78733167367 | 2018 | 49.777476995103 | 2017 | 49.761674034972 | 2016 | 49.737843349106 | 2015 | 49.713695664055 | 2014 | 49.691852026011 | 2013 | 49.673901851216 | 2012 | 49.656614933552 | 2011 | 49.640289373065 | 2010 | 49.634367024067 | 2009 | 49.631629910808 | 2008 | 49.630702632565 | 2007 | 49.626057306482 | 2006 | 49.6020883134 | 2005 | 49.557927799306 | 2004 | 49.498946785347 | 2003 | 49.432308941321 | 2002 | 49.364385764743 | 2001 | 49.298051782875 | 2000 | 49.238324892063 | 1999 | 49.183694809076 | 1998 | 49.130988728481 | 1997 | 49.101969992162 | 1996 | 49.104584129303 | 1995 | 49.111714828455 | 1994 | 49.116195248639 | 1993 | 49.125631664393 | 1992 | 49.141198857536 | 1991 | 49.164842867064 | 1990 | 49.1807847702 | 1989 | 49.181022106895 | 1988 | 49.179717257714 | 1987 | 49.179371276525 | 1986 | 49.177705621719 | 1985 | 49.167502696077 | 1984 | 49.148213836952 | 1983 | 49.12724214413 | 1982 | 49.113901644906 | 1981 | 49.111209998133 | 1980 | 49.112378581926 | 1979 | 49.12056242286 | 1978 | 49.138835464068 | 1977 | 49.162208027374 | 1976 | 49.19946760365 | 1975 | 49.25831367037 | 1974 | 49.331612536164 | 1973 | 49.418187185561 | 1972 | 49.51534662479 | 1971 | 49.620229745543 | 1970 | 49.725910273348 | 1969 | 49.827974343276 | 1968 | 49.933005896772 | 1967 | 50.039348195039 | 1966 | 50.150120250698 | 1965 | 50.265271197025 | 1964 | 50.384989611141 | 1963 | 50.509705479717 | 1962 | 50.638836819273 | 1961 | 50.773496635883 | 1960 | 50.909348626115 |
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