Year | Value | 2021 | 9.057 | 2020 | 8.132 | 2019 | 8.043 | 2018 | 7.972 | 2017 | 8.266 | 2016 | 8.441 | 2015 | 8.774 | 2014 | 9.123 | 2013 | 9.787 | 2012 | 10.691 | 2011 | 11.857 | 2010 | 13.281 | 2009 | 14.804 | 2008 | 15.604 | 2007 | 16.27 | 2006 | 16.436 | 2005 | 16.82 | 2004 | 16.989 | 2003 | 17.805 | 2002 | 16.953 | 2001 | 19.048 | 2000 | 16.801 | 1999 | 16.301 | 1998 | 15.15 | 1997 | 14.357 | 1996 | 13.755 | 1995 | 12.825 | 1994 | 11.755 | 1993 | 10.829 | 1992 | 9.947 | 1991 | 9.259 | 1990 | 8.747 | 1989 | 8.424 | 1988 | 8.17 | 1987 | 8.117 | 1986 | 8.17 | 1985 | 8.492 | 1984 | 8.91 | 1983 | 9.442 | 1982 | 9.776 | 1981 | 10.122 | 1980 | 11.069 | 1979 | 12.561 | 1978 | 12.592 | 1977 | 11.821 | 1976 | 11.561 | 1975 | 11.3 | 1974 | 11.308 | 1973 | 11.339 | 1972 | 11.302 | 1971 | 11.373 | 1970 | 11.441 | 1969 | 11.629 | 1968 | 11.813 | 1967 | 12.02 | 1966 | 12.259 | 1965 | 12.566 | 1964 | 12.899 | 1963 | 13.235 | 1962 | 13.585 | 1961 | 13.919 | 1960 | 14.221 |
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