Year | Value | 2022 | 50.095084690751 | 2021 | 50.070320409122 | 2020 | 50.044845753167 | 2019 | 50.016704552454 | 2018 | 49.985021199437 | 2017 | 49.96015513124 | 2016 | 49.947843480983 | 2015 | 49.924149473382 | 2014 | 49.886835443975 | 2013 | 49.852817500803 | 2012 | 49.818923663511 | 2011 | 49.784692171653 | 2010 | 49.754540838561 | 2009 | 49.728759973905 | 2008 | 49.716033205262 | 2007 | 49.73144759965 | 2006 | 49.763507820472 | 2005 | 49.786080783356 | 2004 | 49.796428063256 | 2003 | 49.798711233215 | 2002 | 49.782830869892 | 2001 | 49.75280290626 | 2000 | 49.721379692067 | 1999 | 49.687906342433 | 1998 | 49.647710576378 | 1997 | 49.602445415004 | 1996 | 49.55545762688 | 1995 | 49.508398023415 | 1994 | 49.462025349276 | 1993 | 49.415111606048 | 1992 | 49.364110848703 | 1991 | 49.324708912923 | 1990 | 49.313926344663 | 1989 | 49.317830666203 | 1988 | 49.353942634712 | 1987 | 49.407872108111 | 1986 | 49.44950902022 | 1985 | 49.49604718997 | 1984 | 49.546394908978 | 1983 | 49.601049723301 | 1982 | 49.658611517726 | 1981 | 49.721274789831 | 1980 | 49.767321164469 | 1979 | 49.764814872187 | 1978 | 49.734366003841 | 1977 | 49.703343255224 | 1976 | 49.672157023277 | 1975 | 49.653758746842 | 1974 | 49.649075089837 | 1973 | 49.632891926786 | 1972 | 49.603785553208 | 1971 | 49.57437413638 | 1970 | 49.545928810794 | 1969 | 49.521148471251 | 1968 | 49.498794905971 | 1967 | 49.476216426238 | 1966 | 49.458415552329 | 1965 | 49.445284373072 | 1964 | 49.433527702808 | 1963 | 49.426008140826 | 1962 | 49.420476161454 | 1961 | 49.420470218218 | 1960 | 49.429684736554 |
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