Year | Value | 2021 | 8.797 | 2020 | 7.583 | 2019 | 7.477 | 2018 | 7.318 | 2017 | 7.145 | 2016 | 6.971 | 2015 | 6.653 | 2014 | 6.238 | 2013 | 5.924 | 2012 | 5.813 | 2011 | 5.871 | 2010 | 6.019 | 2009 | 6.219 | 2008 | 6.429 | 2007 | 6.501 | 2006 | 6.587 | 2005 | 6.654 | 2004 | 6.753 | 2003 | 6.817 | 2002 | 6.81 | 2001 | 6.914 | 2000 | 6.894 | 1999 | 6.979 | 1998 | 7.062 | 1997 | 7.034 | 1996 | 6.975 | 1995 | 7.066 | 1994 | 7.061 | 1993 | 7.063 | 1992 | 7.016 | 1991 | 6.974 | 1990 | 6.861 | 1989 | 6.877 | 1988 | 7.118 | 1987 | 7.206 | 1986 | 7.417 | 1985 | 7.513 | 1984 | 7.645 | 1983 | 7.74 | 1982 | 7.663 | 1981 | 7.843 | 1980 | 7.984 | 1979 | 8.078 | 1978 | 8.125 | 1977 | 8.139 | 1976 | 8.112 | 1975 | 8.233 | 1974 | 8.249 | 1973 | 8.31 | 1972 | 8.428 | 1971 | 8.443 | 1970 | 8.469 | 1969 | 8.596 | 1968 | 8.622 | 1967 | 8.463 | 1966 | 8.421 | 1965 | 8.5 | 1964 | 8.551 | 1963 | 8.575 | 1962 | 8.824 | 1961 | 8.796 | 1960 | 8.838 |
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