Year | Value | 2021 | 9.147 | 2020 | 8.821 | 2019 | 8.421 | 2018 | 8.347 | 2017 | 8.37 | 2016 | 8.568 | 2015 | 8.598 | 2014 | 8.672 | 2013 | 8.807 | 2012 | 8.924 | 2011 | 9.07 | 2010 | 9.11 | 2009 | 9.361 | 2008 | 9.487 | 2007 | 9.643 | 2006 | 9.796 | 2005 | 9.988 | 2004 | 10.258 | 2003 | 10.328 | 2002 | 10.52 | 2001 | 10.676 | 2000 | 10.831 | 1999 | 10.899 | 1998 | 11.041 | 1997 | 11.208 | 1996 | 11.152 | 1995 | 11.141 | 1994 | 11.613 | 1993 | 11.483 | 1992 | 12.113 | 1991 | 11.816 | 1990 | 11.711 | 1989 | 11.855 | 1988 | 11.944 | 1987 | 12.178 | 1986 | 12.368 | 1985 | 12.632 | 1984 | 12.881 | 1983 | 13.225 | 1982 | 13.518 | 1981 | 13.877 | 1980 | 14.123 | 1979 | 14.446 | 1978 | 14.788 | 1977 | 15.144 | 1976 | 15.526 | 1975 | 15.701 | 1974 | 15.963 | 1973 | 16.267 | 1972 | 16.688 | 1971 | 17.494 | 1970 | 17.433 | 1969 | 17.815 | 1968 | 18.207 | 1967 | 18.582 | 1966 | 18.887 | 1965 | 19.143 | 1964 | 19.418 | 1963 | 19.577 | 1962 | 19.78 | 1961 | 20.006 | 1960 | 20.192 |
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