Year | Value | 2021 | 12.162 | 2020 | 9.432 | 2019 | 10.057 | 2018 | 9.863 | 2017 | 9.724 | 2016 | 9.628 | 2015 | 9.559 | 2014 | 9.508 | 2013 | 9.468 | 2012 | 9.434 | 2011 | 9.402 | 2010 | 9.369 | 2009 | 9.332 | 2008 | 9.29 | 2007 | 9.249 | 2006 | 9.206 | 2005 | 9.166 | 2004 | 9.133 | 2003 | 9.111 | 2002 | 9.101 | 2001 | 9.103 | 2000 | 9.124 | 1999 | 9.165 | 1998 | 9.214 | 1997 | 9.269 | 1996 | 9.321 | 1995 | 9.363 | 1994 | 9.39 | 1993 | 9.4 | 1992 | 9.401 | 1991 | 9.395 | 1990 | 9.388 | 1989 | 9.393 | 1988 | 9.395 | 1987 | 9.395 | 1986 | 9.41 | 1985 | 9.423 | 1984 | 9.434 | 1983 | 9.448 | 1982 | 9.467 | 1981 | 9.49 | 1980 | 9.525 | 1979 | 9.591 | 1978 | 9.667 | 1977 | 9.742 | 1976 | 9.816 | 1975 | 9.846 | 1974 | 9.832 | 1973 | 9.78 | 1972 | 9.761 | 1971 | 9.652 | 1970 | 9.585 | 1969 | 9.559 | 1968 | 9.549 | 1967 | 9.559 | 1966 | 9.579 | 1965 | 9.604 | 1964 | 9.629 | 1963 | 9.649 | 1962 | 9.663 | 1961 | 9.686 | 1960 | 9.727 |
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