Year | Value | 2021 | 13.425 | 2020 | 11.038 | 2019 | 10.1 | 2018 | 8.906 | 2017 | 8.592 | 2016 | 8.385 | 2015 | 8.105 | 2014 | 7.858 | 2013 | 7.98 | 2012 | 7.654 | 2011 | 7.187 | 2010 | 6.916 | 2009 | 6.526 | 2008 | 6.337 | 2007 | 6.319 | 2006 | 6.47 | 2005 | 6.555 | 2004 | 6.649 | 2003 | 6.858 | 2002 | 6.801 | 2001 | 6.848 | 2000 | 7.056 | 1999 | 7.013 | 1998 | 7.06 | 1997 | 7.098 | 1996 | 6.854 | 1995 | 6.385 | 1994 | 6.388 | 1993 | 6.064 | 1992 | 5.885 | 1991 | 5.682 | 1990 | 5.904 | 1989 | 5.75 | 1988 | 5.878 | 1987 | 5.987 | 1986 | 6.119 | 1985 | 6.135 | 1984 | 6.229 | 1983 | 6.287 | 1982 | 6.437 | 1981 | 6.383 | 1980 | 6.396 | 1979 | 6.523 | 1978 | 6.531 | 1977 | 6.468 | 1976 | 6.557 | 1975 | 6.563 | 1974 | 6.65 | 1973 | 6.799 | 1972 | 6.821 | 1971 | 6.757 | 1970 | 6.839 | 1969 | 7.027 | 1968 | 7.339 | 1967 | 7.775 | 1966 | 8.314 | 1965 | 9.072 | 1964 | 10.007 | 1963 | 11.065 | 1962 | 12.232 | 1961 | 13.408 | 1960 | 14.492 |
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