Year | Value | 2022 | 49.823218305822 | 2021 | 49.790548965616 | 2020 | 49.748619594199 | 2019 | 49.710812890638 | 2018 | 49.682054698463 | 2017 | 49.654333083754 | 2016 | 49.626258312442 | 2015 | 49.596783803544 | 2014 | 49.565318030386 | 2013 | 49.532004909693 | 2012 | 49.497272522994 | 2011 | 49.461763776643 | 2010 | 49.426320524604 | 2009 | 49.392256122759 | 2008 | 49.360964692866 | 2007 | 49.333358575636 | 2006 | 49.309663504581 | 2005 | 49.2894310036 | 2004 | 49.271363766095 | 2003 | 49.253732012594 | 2002 | 49.234011070481 | 2001 | 49.274394858023 | 2000 | 49.378927548982 | 1999 | 49.486421600086 | 1998 | 49.598400217529 | 1997 | 49.71597810867 | 1996 | 49.839459611792 | 1995 | 49.968518707004 | 1994 | 50.105360817428 | 1993 | 50.176899011282 | 1992 | 50.175675275401 | 1991 | 50.17322483699 | 1990 | 50.169995696453 | 1989 | 50.166811532266 | 1988 | 50.164444828785 | 1987 | 50.163132478275 | 1986 | 50.163075526465 | 1985 | 50.163778916071 | 1984 | 50.164658210052 | 1983 | 50.165351355159 | 1982 | 50.165212546877 | 1981 | 50.164105345505 | 1980 | 50.161836755968 | 1979 | 50.157789096928 | 1978 | 50.151079721871 | 1977 | 50.142067005972 | 1976 | 50.131701646395 | 1975 | 50.120288975537 | 1974 | 50.107721435541 | 1973 | 50.094028611166 | 1972 | 50.079082695758 | 1971 | 50.062426070814 | 1970 | 50.044203686836 | 1969 | 50.026855326291 | 1968 | 50.010766089395 | 1967 | 49.993842658258 | 1966 | 49.975847046342 | 1965 | 49.932975109028 | 1964 | 49.887043005208 | 1963 | 49.863166215505 | 1962 | 49.83772411623 | 1961 | 49.809867636423 | 1960 | 49.780277323886 |
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