Year | Value | 2022 | 49.511888398771 | 2021 | 49.498659560464 | 2020 | 49.485282356443 | 2019 | 49.474039568307 | 2018 | 49.464854460142 | 2017 | 49.456083313718 | 2016 | 49.447868985259 | 2015 | 49.440126182083 | 2014 | 49.4337327777 | 2013 | 49.427793073655 | 2012 | 49.422061203769 | 2011 | 49.418417202242 | 2010 | 49.417028865334 | 2009 | 49.418192063066 | 2008 | 49.421244252958 | 2007 | 49.425437335683 | 2006 | 49.430124464184 | 2005 | 49.435086765179 | 2004 | 49.438951421749 | 2003 | 49.443166306136 | 2002 | 49.44940873869 | 2001 | 49.454120228533 | 2000 | 49.45772883813 | 1999 | 49.461856788987 | 1998 | 49.474212483814 | 1997 | 49.486760658009 | 1996 | 49.48963867114 | 1995 | 49.491160246847 | 1994 | 49.491662205856 | 1993 | 49.490953076503 | 1992 | 49.489651012372 | 1991 | 49.488337922298 | 1990 | 49.487061157271 | 1989 | 49.485049482302 | 1988 | 49.482201554839 | 1987 | 49.485710866294 | 1986 | 49.497427566145 | 1985 | 49.512032861005 | 1984 | 49.526961915513 | 1983 | 49.541252032489 | 1982 | 49.556895812804 | 1981 | 49.575381904729 | 1980 | 49.59639914346 | 1979 | 49.618700337671 | 1978 | 49.642938422158 | 1977 | 49.66845116215 | 1976 | 49.695035465246 | 1975 | 49.723189312146 | 1974 | 49.754267362848 | 1973 | 49.779877671525 | 1972 | 49.795146922163 | 1971 | 49.807898933601 | 1970 | 49.82030385018 | 1969 | 49.831882285394 | 1968 | 49.843155614488 | 1967 | 49.853365872462 | 1966 | 49.862054222167 | 1965 | 49.86970894105 | 1964 | 49.874919254382 | 1963 | 49.880055104096 | 1962 | 49.886510862726 | 1961 | 49.89121129309 | 1960 | 49.89327038122 |
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