Year | Value | 2021 | 9.99 | 2020 | 9.847 | 2019 | 9.712 | 2018 | 9.94 | 2017 | 10.121 | 2016 | 10.352 | 2015 | 10.702 | 2014 | 10.856 | 2013 | 10.947 | 2012 | 11.193 | 2011 | 11.451 | 2010 | 11.669 | 2009 | 11.918 | 2008 | 12.12 | 2007 | 12.427 | 2006 | 12.717 | 2005 | 13.037 | 2004 | 13.39 | 2003 | 13.733 | 2002 | 14.094 | 2001 | 14.543 | 2000 | 14.804 | 1999 | 15.028 | 1998 | 15.388 | 1997 | 15.935 | 1996 | 16.551 | 1995 | 17.107 | 1994 | 17.707 | 1993 | 17.994 | 1992 | 18.476 | 1991 | 19.077 | 1990 | 19.494 | 1989 | 19.669 | 1988 | 19.891 | 1987 | 20.031 | 1986 | 20.378 | 1985 | 20.659 | 1984 | 21.062 | 1983 | 21.463 | 1982 | 21.786 | 1981 | 22.216 | 1980 | 22.545 | 1979 | 22.899 | 1978 | 23.233 | 1977 | 23.599 | 1976 | 23.898 | 1975 | 24.258 | 1974 | 24.641 | 1973 | 24.852 | 1972 | 25.032 | 1971 | 25.348 | 1970 | 25.616 | 1969 | 25.885 | 1968 | 26.063 | 1967 | 26.504 | 1966 | 26.82 | 1965 | 27.104 | 1964 | 27.409 | 1963 | 27.638 | 1962 | 27.936 | 1961 | 28.144 | 1960 | 28.389 |
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