Year | Value | 2021 | 9.434 | 2020 | 9.364 | 2019 | 9.248 | 2018 | 9.428 | 2017 | 9.592 | 2016 | 9.761 | 2015 | 9.857 | 2014 | 9.996 | 2013 | 10.085 | 2012 | 10.224 | 2011 | 10.372 | 2010 | 10.461 | 2009 | 10.7 | 2008 | 10.798 | 2007 | 10.961 | 2006 | 11.128 | 2005 | 11.337 | 2004 | 11.546 | 2003 | 11.649 | 2002 | 11.77 | 2001 | 11.825 | 2000 | 11.964 | 1999 | 12.103 | 1998 | 12.36 | 1997 | 12.596 | 1996 | 12.927 | 1995 | 13.192 | 1994 | 13.473 | 1993 | 13.748 | 1992 | 14.088 | 1991 | 14.461 | 1990 | 14.75 | 1989 | 15.2 | 1988 | 15.543 | 1987 | 16.01 | 1986 | 16.451 | 1985 | 16.963 | 1984 | 17.44 | 1983 | 17.79 | 1982 | 18.219 | 1981 | 18.61 | 1980 | 18.929 | 1979 | 19.298 | 1978 | 19.63 | 1977 | 20.28 | 1976 | 20.869 | 1975 | 21.569 | 1974 | 22.128 | 1973 | 22.631 | 1972 | 23.096 | 1971 | 23.668 | 1970 | 24.108 | 1969 | 24.51 | 1968 | 24.908 | 1967 | 25.435 | 1966 | 25.915 | 1965 | 26.432 | 1964 | 26.896 | 1963 | 27.345 | 1962 | 27.765 | 1961 | 28.142 | 1960 | 28.468 |
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