Year | Value | 2021 | 13.007 | 2020 | 12.792 | 2019 | 9.662 | 2018 | 9.75 | 2017 | 9.664 | 2016 | 9.634 | 2015 | 9.607 | 2014 | 9.704 | 2013 | 9.813 | 2012 | 9.761 | 2011 | 9.559 | 2010 | 9.384 | 2009 | 9.356 | 2008 | 9.387 | 2007 | 9.117 | 2006 | 9.063 | 2005 | 8.914 | 2004 | 8.919 | 2003 | 8.573 | 2002 | 8.593 | 2001 | 8.344 | 2000 | 8.27 | 1999 | 8.261 | 1998 | 7.808 | 1997 | 7.994 | 1996 | 7.837 | 1995 | 7.969 | 1994 | 7.869 | 1993 | 7.803 | 1992 | 7.67 | 1991 | 7.664 | 1990 | 7.524 | 1989 | 7.556 | 1988 | 14.853 | 1987 | 7.743 | 1986 | 7.566 | 1985 | 7.592 | 1984 | 7.684 | 1983 | 7.705 | 1982 | 7.717 | 1981 | 7.735 | 1980 | 7.803 | 1979 | 7.738 | 1978 | 7.864 | 1977 | 7.976 | 1976 | 7.993 | 1975 | 8.036 | 1974 | 8.046 | 1973 | 8.115 | 1972 | 8.123 | 1971 | 8.292 | 1970 | 8.491 | 1969 | 8.663 | 1968 | 8.943 | 1967 | 9.144 | 1966 | 9.489 | 1965 | 9.853 | 1964 | 10.365 | 1963 | 10.831 | 1962 | 11.213 | 1961 | 11.715 | 1960 | 12.201 |
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