Year | Value | 2022 | 49.459806255081 | 2021 | 49.420784654247 | 2020 | 49.366719660837 | 2019 | 49.319524751682 | 2018 | 49.274880210748 | 2017 | 49.229311220173 | 2016 | 49.175413315346 | 2015 | 49.114251148955 | 2014 | 49.053206059205 | 2013 | 48.988306854794 | 2012 | 48.926318287134 | 2011 | 48.871400276936 | 2010 | 48.816369966313 | 2009 | 48.760640917094 | 2008 | 48.707575617163 | 2007 | 48.649785389211 | 2006 | 48.601496538754 | 2005 | 48.571165055707 | 2004 | 48.546411511912 | 2003 | 48.519794963769 | 2002 | 48.477446292887 | 2001 | 48.414618367451 | 2000 | 48.343940668003 | 1999 | 48.270203912957 | 1998 | 48.197890333578 | 1997 | 48.121621847755 | 1996 | 48.0604960266 | 1995 | 48.019408414922 | 1994 | 47.975246176685 | 1993 | 47.929499271391 | 1992 | 47.881577809044 | 1991 | 47.832847514899 | 1990 | 47.784583753772 | 1989 | 47.735645371325 | 1988 | 47.704966788936 | 1987 | 47.692729711058 | 1986 | 47.678931923661 | 1985 | 47.661772702556 | 1984 | 47.643410175488 | 1983 | 47.618994425889 | 1982 | 47.568872854087 | 1981 | 47.493072496033 | 1980 | 47.412754980409 | 1979 | 47.326929989972 | 1978 | 47.234706819734 | 1977 | 47.294422409685 | 1976 | 47.499930726814 | 1975 | 47.691889611179 | 1974 | 47.888791199048 | 1973 | 48.093335268904 | 1972 | 48.299421937892 | 1971 | 48.429259344187 | 1970 | 48.475286493456 | 1969 | 48.508387300862 | 1968 | 48.530482919368 | 1967 | 48.55134676164 | 1966 | 48.567182565677 | 1965 | 48.580173095243 | 1964 | 48.591268173796 | 1963 | 48.583669519263 | 1962 | 48.544973544974 | 1961 | 48.499211928073 | 1960 | 48.450813779449 |
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