Year | Value | 2021 | 9.001 | 2020 | 8.817 | 2019 | 8.728 | 2018 | 8.961 | 2017 | 9.17 | 2016 | 9.374 | 2015 | 9.543 | 2014 | 9.847 | 2013 | 10.144 | 2012 | 10.517 | 2011 | 10.927 | 2010 | 11.187 | 2009 | 11.529 | 2008 | 11.952 | 2007 | 12.364 | 2006 | 12.753 | 2005 | 13.117 | 2004 | 13.465 | 2003 | 13.795 | 2002 | 13.933 | 2001 | 14.148 | 2000 | 14.291 | 1999 | 14.365 | 1998 | 14.379 | 1997 | 14.255 | 1996 | 14.254 | 1995 | 14.249 | 1994 | 14.21 | 1993 | 14.173 | 1992 | 14.107 | 1991 | 14.03 | 1990 | 13.882 | 1989 | 13.698 | 1988 | 13.547 | 1987 | 13.579 | 1986 | 13.753 | 1985 | 13.957 | 1984 | 14.228 | 1983 | 14.359 | 1982 | 14.663 | 1981 | 14.925 | 1980 | 15.3 | 1979 | 15.7 | 1978 | 16.168 | 1977 | 16.626 | 1976 | 17.134 | 1975 | 17.851 | 1974 | 18.518 | 1973 | 19.256 | 1972 | 19.929 | 1971 | 20.568 | 1970 | 21.167 | 1969 | 21.788 | 1968 | 22.364 | 1967 | 22.925 | 1966 | 23.484 | 1965 | 24.079 | 1964 | 24.619 | 1963 | 25.213 | 1962 | 25.73 | 1961 | 26.332 | 1960 | 26.907 |
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