Year | Value | 2022 | 52.054316577614 | 2021 | 52.152591099667 | 2020 | 52.364231553319 | 2019 | 52.469574607762 | 2018 | 52.452699560721 | 2017 | 52.43375663413 | 2016 | 52.408817054665 | 2015 | 52.326363416584 | 2014 | 52.155945359762 | 2013 | 51.92058303482 | 2012 | 51.658541857737 | 2011 | 51.405185554572 | 2010 | 51.180725324132 | 2009 | 50.972364945038 | 2008 | 50.761388557145 | 2007 | 50.554991445386 | 2006 | 50.354291650306 | 2005 | 50.166794051841 | 2004 | 49.998159896001 | 2003 | 49.848549081747 | 2002 | 49.715279120492 | 2001 | 49.607452230762 | 2000 | 49.519941366885 | 1999 | 49.439222053686 | 1998 | 49.367759666491 | 1997 | 49.30412663681 | 1996 | 49.247635475628 | 1995 | 49.195445388957 | 1994 | 49.164668135002 | 1993 | 49.150536274861 | 1992 | 49.148365533155 | 1991 | 49.163104915115 | 1990 | 49.182602631556 | 1989 | 49.190912107588 | 1988 | 49.175372027128 | 1987 | 49.146648154741 | 1986 | 49.124866769256 | 1985 | 49.120937967185 | 1984 | 49.128809954257 | 1983 | 49.150947656556 | 1982 | 49.179488697828 | 1981 | 49.203352178914 | 1980 | 49.23120126981 | 1979 | 49.261242726021 | 1978 | 49.287469683527 | 1977 | 49.316618134309 | 1976 | 49.338797467847 | 1975 | 49.35601424749 | 1974 | 49.379483104035 | 1973 | 49.405063586334 | 1972 | 49.431062302045 | 1971 | 49.456886841118 | 1970 | 49.483065140903 | 1969 | 49.512208840608 | 1968 | 49.5443974313 | 1967 | 49.577174120033 | 1966 | 49.613184566371 | 1965 | 49.650870906496 | 1964 | 49.688475289833 | 1963 | 49.726808187584 | 1962 | 49.76583421596 | 1961 | 49.803639968726 | 1960 | 49.840729799671 |
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