Year | Value | 2021 | 2.462 | 2020 | 2.507 | 2019 | 2.539 | 2018 | 2.581 | 2017 | 2.626 | 2016 | 2.673 | 2015 | 2.711 | 2014 | 2.754 | 2013 | 2.716 | 2012 | 2.68 | 2011 | 2.646 | 2010 | 2.603 | 2009 | 2.556 | 2008 | 2.599 | 2007 | 2.648 | 2006 | 2.699 | 2005 | 2.765 | 2004 | 2.808 | 2003 | 2.857 | 2002 | 2.911 | 2001 | 2.971 | 2000 | 2.851 | 1999 | 2.97 | 1998 | 3.109 | 1997 | 3.265 | 1996 | 3.439 | 1995 | 3.636 | 1994 | 3.859 | 1993 | 4.109 | 1992 | 4.381 | 1991 | 4.67 | 1990 | 4.966 | 1989 | 5.256 | 1988 | 5.533 | 1987 | 5.79 | 1986 | 6.023 | 1985 | 6.236 | 1984 | 6.435 | 1983 | 6.63 | 1982 | 6.826 | 1981 | 7.023 | 1980 | 7.219 | 1979 | 7.581 | 1978 | 7.714 | 1977 | 7.815 | 1976 | 7.9 | 1975 | 7.964 | 1974 | 8.022 | 1973 | 8.068 | 1972 | 8.099 | 1971 | 8.133 | 1970 | 8.097 | 1969 | 8.075 | 1968 | 8.045 | 1967 | 8.024 | 1966 | 7.994 | 1965 | 7.912 | 1964 | 7.817 | 1963 | 7.697 | 1962 | 7.551 | 1961 | 7.446 | 1960 | 7.373 |
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