Year | Value | 2021 | 8.529 | 2020 | 8.605 | 2019 | 8.888 | 2018 | 8.94 | 2017 | 9.25 | 2016 | 9.359 | 2015 | 9.586 | 2014 | 9.831 | 2013 | 10.603 | 2012 | 10.908 | 2011 | 11.452 | 2010 | 12.826 | 2009 | 13.068 | 2008 | 12.449 | 2007 | 11.801 | 2006 | 11.655 | 2005 | 11.541 | 2004 | 11.148 | 2003 | 11.344 | 2002 | 12.071 | 2001 | 11.755 | 2000 | 11.33 | 1999 | 12.109 | 1998 | 12.827 | 1997 | 12.244 | 1996 | 11.613 | 1995 | 12.403 | 1994 | 12.97 | 1993 | 12.463 | 1992 | 12.455 | 1991 | 13.047 | 1990 | 12.932 | 1989 | 12.671 | 1988 | 12.386 | 1987 | 12.131 | 1986 | 11.893 | 1985 | 11.864 | 1984 | 11.863 | 1983 | 11.907 | 1982 | 11.949 | 1981 | 12.007 | 1980 | 11.937 | 1979 | 11.952 | 1978 | 11.903 | 1977 | 11.931 | 1976 | 12.049 | 1975 | 12.218 | 1974 | 13.637 | 1973 | 15.113 | 1972 | 16.436 | 1971 | 16.361 | 1970 | 16.272 | 1969 | 12.88 | 1968 | 12.933 | 1967 | 13.017 | 1966 | 13.264 | 1965 | 13.54 | 1964 | 13.613 | 1963 | 13.551 | 1962 | 13.378 | 1961 | 14.034 | 1960 | 14.959 |
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