Year | Value | 2021 | 6.838 | 2020 | 6.228 | 2019 | 5.947 | 2018 | 5.874 | 2017 | 5.775 | 2016 | 5.779 | 2015 | 5.81 | 2014 | 5.756 | 2013 | 5.817 | 2012 | 5.863 | 2011 | 5.947 | 2010 | 6.121 | 2009 | 6.127 | 2008 | 6.418 | 2007 | 6.63 | 2006 | 6.809 | 2005 | 7.042 | 2004 | 7.273 | 2003 | 7.641 | 2002 | 8.149 | 2001 | 8.667 | 2000 | 9.273 | 1999 | 9.749 | 1998 | 10.151 | 1997 | 10.467 | 1996 | 10.847 | 1995 | 11.064 | 1994 | 11.38 | 1993 | 11.528 | 1992 | 11.75 | 1991 | 11.986 | 1990 | 12.246 | 1989 | 12.727 | 1988 | 13.168 | 1987 | 13.742 | 1986 | 14.902 | 1985 | 15.257 | 1984 | 15.731 | 1983 | 16.131 | 1982 | 16.469 | 1981 | 16.694 | 1980 | 16.53 | 1979 | 19.061 | 1978 | 22.627 | 1977 | 31.701 | 1976 | 86.575 | 1975 | 85.733 | 1974 | 21.628 | 1973 | 21.816 | 1972 | 21.743 | 1971 | 22.319 | 1970 | 22.577 | 1969 | 17.368 | 1968 | 17.71 | 1967 | 17.936 | 1966 | 18.096 | 1965 | 18.545 | 1964 | 18.862 | 1963 | 19.292 | 1962 | 19.883 | 1961 | 20.439 | 1960 | 20.951 |
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