Year | Value | 2021 | 7.344 | 2020 | 7.113 | 2019 | 6.791 | 2018 | 6.981 | 2017 | 7.027 | 2016 | 7.077 | 2015 | 7.331 | 2014 | 7.395 | 2013 | 7.478 | 2012 | 7.711 | 2011 | 7.931 | 2010 | 8.254 | 2009 | 8.535 | 2008 | 8.832 | 2007 | 9.359 | 2006 | 9.679 | 2005 | 9.941 | 2004 | 10.277 | 2003 | 10.698 | 2002 | 11.28 | 2001 | 11.713 | 2000 | 12.096 | 1999 | 12.463 | 1998 | 13.565 | 1997 | 13.334 | 1996 | 13.627 | 1995 | 14.092 | 1994 | 14.689 | 1993 | 14.838 | 1992 | 17.222 | 1991 | 17.946 | 1990 | 18.449 | 1989 | 19.047 | 1988 | 19.945 | 1987 | 23.285 | 1986 | 23.705 | 1985 | 29.661 | 1984 | 30.03 | 1983 | 25.107 | 1982 | 25.622 | 1981 | 23.611 | 1980 | 24.209 | 1979 | 24.797 | 1978 | 23.875 | 1977 | 23.179 | 1976 | 23.718 | 1975 | 24.241 | 1974 | 24.773 | 1973 | 25.297 | 1972 | 25.845 | 1971 | 26.364 | 1970 | 26.875 | 1969 | 27.398 | 1968 | 27.895 | 1967 | 28.396 | 1966 | 28.872 | 1965 | 29.389 | 1964 | 29.867 | 1963 | 30.359 | 1962 | 30.845 | 1961 | 31.349 | 1960 | 31.921 |
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