Year | Value | 2021 | 6.683 | 2020 | 6.402 | 2019 | 6.468 | 2018 | 6.532 | 2017 | 6.508 | 2016 | 6.57 | 2015 | 6.585 | 2014 | 6.734 | 2013 | 6.825 | 2012 | 6.891 | 2011 | 6.951 | 2010 | 7.134 | 2009 | 7.215 | 2008 | 7.287 | 2007 | 7.501 | 2006 | 7.532 | 2005 | 7.563 | 2004 | 7.559 | 2003 | 7.524 | 2002 | 7.54 | 2001 | 7.473 | 2000 | 7.471 | 1999 | 7.468 | 1998 | 7.917 | 1997 | 7.536 | 1996 | 7.621 | 1995 | 7.618 | 1994 | 7.726 | 1993 | 7.816 | 1992 | 7.918 | 1991 | 8.046 | 1990 | 8.119 | 1989 | 8.179 | 1988 | 8.281 | 1987 | 8.324 | 1986 | 8.421 | 1985 | 8.445 | 1984 | 8.542 | 1983 | 8.615 | 1982 | 8.692 | 1981 | 8.788 | 1980 | 8.952 | 1979 | 9.158 | 1978 | 9.395 | 1977 | 9.68 | 1976 | 9.962 | 1975 | 10.293 | 1974 | 10.668 | 1973 | 11.092 | 1972 | 11.555 | 1971 | 12.005 | 1970 | 12.361 | 1969 | 12.848 | 1968 | 13.264 | 1967 | 13.748 | 1966 | 14.196 | 1965 | 14.671 | 1964 | 15.105 | 1963 | 15.527 | 1962 | 16.178 | 1961 | 16.431 | 1960 | 16.888 |
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