Year | Value | 2022 | 47.59617487861 | 2021 | 47.545806367923 | 2020 | 47.456259933014 | 2019 | 47.336772239324 | 2018 | 47.252472360433 | 2017 | 47.233319014854 | 2016 | 47.303242870496 | 2015 | 47.473853655455 | 2014 | 47.689194316418 | 2013 | 47.860672657564 | 2012 | 47.966601283786 | 2011 | 48.03699020599 | 2010 | 48.070368573774 | 2009 | 48.14074577617 | 2008 | 48.364319593092 | 2007 | 48.716855942033 | 2006 | 49.124454870718 | 2005 | 49.462862397875 | 2004 | 49.624858143491 | 2003 | 49.700272030229 | 2002 | 49.765342610036 | 2001 | 49.816587330429 | 2000 | 49.865625846466 | 1999 | 49.908034862794 | 1998 | 49.942479784243 | 1997 | 49.96895599201 | 1996 | 49.982296224538 | 1995 | 49.986704222559 | 1994 | 49.990509132099 | 1993 | 49.993747724622 | 1992 | 49.9913209369 | 1991 | 49.986972592142 | 1990 | 49.995614315438 | 1989 | 50.01630658514 | 1988 | 50.034057400277 | 1987 | 50.048178145269 | 1986 | 50.059659593329 | 1985 | 50.079182140108 | 1984 | 50.112716347503 | 1983 | 50.146791918939 | 1982 | 50.18018581595 | 1981 | 50.22117451802 | 1980 | 50.279557346056 | 1979 | 50.358410516011 | 1978 | 50.442622768305 | 1977 | 50.525466129304 | 1976 | 50.615621161963 | 1975 | 50.712786592581 | 1974 | 50.801886743103 | 1973 | 50.893346388384 | 1972 | 50.998593741614 | 1971 | 51.098239333962 | 1970 | 51.180077380485 | 1969 | 51.243528774738 | 1968 | 51.303777272105 | 1967 | 51.368704011439 | 1966 | 51.413219150308 | 1965 | 51.43355749752 | 1964 | 51.45934202784 | 1963 | 51.493595505956 | 1962 | 51.535554336236 | 1961 | 51.582079081331 | 1960 | 51.627007755343 |
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