Year | Value | 2021 | 6.236 | 2020 | 6.242 | 2019 | 6.252 | 2018 | 6.345 | 2017 | 6.426 | 2016 | 6.519 | 2015 | 6.623 | 2014 | 6.727 | 2013 | 6.831 | 2012 | 6.928 | 2011 | 7.007 | 2010 | 7.071 | 2009 | 7.102 | 2008 | 7.102 | 2007 | 7.064 | 2006 | 7.004 | 2005 | 6.917 | 2004 | 6.857 | 2003 | 6.829 | 2002 | 6.875 | 2001 | 6.95 | 2000 | 7.09 | 1999 | 7.255 | 1998 | 7.433 | 1997 | 7.613 | 1996 | 7.801 | 1995 | 7.952 | 1994 | 8.142 | 1993 | 8.369 | 1992 | 8.633 | 1991 | 8.912 | 1990 | 9.229 | 1989 | 9.539 | 1988 | 9.843 | 1987 | 10.143 | 1986 | 10.411 | 1985 | 10.601 | 1984 | 10.74 | 1983 | 10.853 | 1982 | 10.952 | 1981 | 11.014 | 1980 | 11.084 | 1979 | 11.096 | 1978 | 11.308 | 1977 | 11.87 | 1976 | 11.659 | 1975 | 11.84 | 1974 | 12.013 | 1973 | 12.322 | 1972 | 12.765 | 1971 | 13.18 | 1970 | 13.729 | 1969 | 14.335 | 1968 | 14.783 | 1967 | 15.243 | 1966 | 15.66 | 1965 | 16.291 | 1964 | 16.942 | 1963 | 17.623 | 1962 | 18.298 | 1961 | 18.901 | 1960 | 19.411 |
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