Year | Value | 2021 | 9.769 | 2020 | 8.819 | 2019 | 8.692 | 2018 | 8.622 | 2017 | 8.808 | 2016 | 8.753 | 2015 | 8.673 | 2014 | 8.804 | 2013 | 8.799 | 2012 | 9.023 | 2011 | 9.026 | 2010 | 9.214 | 2009 | 9.193 | 2008 | 12.149 | 2007 | 9.409 | 2006 | 9.562 | 2005 | 9.628 | 2004 | 9.736 | 2003 | 9.812 | 2002 | 9.876 | 2001 | 9.943 | 2000 | 9.995 | 1999 | 10.07 | 1998 | 10.06 | 1997 | 10.296 | 1996 | 10.411 | 1995 | 10.737 | 1994 | 10.872 | 1993 | 11.023 | 1992 | 11.203 | 1991 | 11.31 | 1990 | 11.489 | 1989 | 11.528 | 1988 | 11.795 | 1987 | 11.849 | 1986 | 12.017 | 1985 | 12.211 | 1984 | 12.35 | 1983 | 12.505 | 1982 | 12.627 | 1981 | 12.796 | 1980 | 12.973 | 1979 | 13.227 | 1978 | 13.507 | 1977 | 13.626 | 1976 | 13.832 | 1975 | 14.127 | 1974 | 14.322 | 1973 | 14.591 | 1972 | 14.855 | 1971 | 15.063 | 1970 | 15.398 | 1969 | 15.664 | 1968 | 15.857 | 1967 | 16.42 | 1966 | 17.085 | 1965 | 17.762 | 1964 | 18.487 | 1963 | 19.172 | 1962 | 19.695 | 1961 | 20.241 | 1960 | 20.696 |
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