Year | Value | 2022 | 50.458833940371 | 2021 | 50.445093587458 | 2020 | 50.431230376969 | 2019 | 50.409374679219 | 2018 | 50.39114737064 | 2017 | 50.384167027956 | 2016 | 50.363824549946 | 2015 | 50.327992916093 | 2014 | 50.280570572973 | 2013 | 50.227962149859 | 2012 | 50.161185689102 | 2011 | 50.066729772784 | 2010 | 49.982810950519 | 2009 | 49.92792800628 | 2008 | 49.858450623593 | 2007 | 49.74839566271 | 2006 | 49.646681128243 | 2005 | 49.597085790156 | 2004 | 49.577671381757 | 2003 | 49.5653718692 | 2002 | 49.558063809619 | 2001 | 49.55129765794 | 2000 | 49.526785925015 | 1999 | 49.493539201576 | 1998 | 49.472276402878 | 1997 | 49.456987701043 | 1996 | 49.447952874694 | 1995 | 49.448160991601 | 1994 | 49.450866192316 | 1993 | 49.456696170993 | 1992 | 49.456825139617 | 1991 | 49.444705935353 | 1990 | 49.444223879654 | 1989 | 49.461897284032 | 1988 | 49.462984241219 | 1987 | 49.441084337465 | 1986 | 49.435687309701 | 1985 | 49.445834056769 | 1984 | 49.462892806809 | 1983 | 49.486263046884 | 1982 | 49.504499589422 | 1981 | 49.529239448712 | 1980 | 49.55712207424 | 1979 | 49.578738969414 | 1978 | 49.600486054153 | 1977 | 49.626412284236 | 1976 | 49.650027295437 | 1975 | 49.67263602486 | 1974 | 49.692501091489 | 1973 | 49.708600152144 | 1972 | 49.725213047289 | 1971 | 49.732046088688 | 1970 | 49.742333080294 | 1969 | 49.759962323792 | 1968 | 49.772711669791 | 1967 | 49.778561239972 | 1966 | 49.79319635595 | 1965 | 49.811280216785 | 1964 | 49.813474697219 | 1963 | 49.813106796117 | 1962 | 49.816700846053 | 1961 | 49.818600856788 | 1960 | 49.818764100159 |
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