Year | Value | 2022 | 50.078068836519 | 2021 | 50.058096506359 | 2020 | 50.040110182933 | 2019 | 50.014382141521 | 2018 | 49.981562361519 | 2017 | 49.949340575244 | 2016 | 49.916636107312 | 2015 | 49.91989610781 | 2014 | 49.966125073314 | 2013 | 50.019117442255 | 2012 | 50.074250237009 | 2011 | 50.131743259562 | 2010 | 50.151746330417 | 2009 | 50.124383544017 | 2008 | 50.088915747319 | 2007 | 50.054083730727 | 2006 | 50.01992847062 | 2005 | 49.977948226851 | 2004 | 49.925854780971 | 2003 | 49.873110365059 | 2002 | 49.822912474524 | 2001 | 49.773323114796 | 2000 | 49.747377517737 | 1999 | 49.74678014681 | 1998 | 49.746690067184 | 1997 | 49.744276804735 | 1996 | 49.743200682047 | 1995 | 49.746637276796 | 1994 | 49.753789262579 | 1993 | 49.76330352078 | 1992 | 49.769660052145 | 1991 | 49.771602807554 | 1990 | 49.794325884435 | 1989 | 49.83583180054 | 1988 | 49.873478821232 | 1987 | 49.907816845239 | 1986 | 49.941134272793 | 1985 | 49.957348181998 | 1984 | 49.949986918521 | 1983 | 49.936432915092 | 1982 | 49.918989269511 | 1981 | 49.899076743062 | 1980 | 49.867351754173 | 1979 | 49.825091039734 | 1978 | 49.78316358239 | 1977 | 49.742604554302 | 1976 | 49.702704496779 | 1975 | 49.677287057133 | 1974 | 49.681149176692 | 1973 | 49.694205488661 | 1972 | 49.702163393541 | 1971 | 49.707962561939 | 1970 | 49.699781998441 | 1969 | 49.679304174305 | 1968 | 49.657991465157 | 1967 | 49.637868887693 | 1966 | 49.61971758435 | 1965 | 49.633548070391 | 1964 | 49.68740912547 | 1963 | 49.754419078737 | 1962 | 49.82607702665 | 1961 | 49.894037128715 | 1960 | 49.932636853047 |
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