Year | Value | 2021 | 6.255 | 2020 | 6.346 | 2019 | 6.412 | 2018 | 6.464 | 2017 | 6.537 | 2016 | 6.623 | 2015 | 6.706 | 2014 | 6.781 | 2013 | 6.839 | 2012 | 6.905 | 2011 | 6.948 | 2010 | 6.99 | 2009 | 7.021 | 2008 | 7.063 | 2007 | 7.092 | 2006 | 7.118 | 2005 | 7.134 | 2004 | 7.16 | 2003 | 7.179 | 2002 | 7.201 | 2001 | 7.231 | 2000 | 7.249 | 1999 | 7.262 | 1998 | 7.266 | 1997 | 7.274 | 1996 | 7.292 | 1995 | 7.29 | 1994 | 7.31 | 1993 | 7.337 | 1992 | 7.296 | 1991 | 7.261 | 1990 | 7.219 | 1989 | 7.186 | 1988 | 7.154 | 1987 | 7.105 | 1986 | 7.067 | 1985 | 7.037 | 1984 | 7.015 | 1983 | 6.979 | 1982 | 6.961 | 1981 | 6.942 | 1980 | 6.908 | 1979 | 6.905 | 1978 | 6.891 | 1977 | 6.896 | 1976 | 6.893 | 1975 | 6.876 | 1974 | 6.864 | 1973 | 6.869 | 1972 | 6.85 | 1971 | 6.582 | 1970 | 6.528 | 1969 | 6.477 | 1968 | 6.432 | 1967 | 6.393 | 1966 | 6.362 | 1965 | 6.337 | 1964 | 6.318 | 1963 | 6.301 | 1962 | 6.285 | 1961 | 6.268 | 1960 | 6.25 |
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