Year | Value | 2021 | 8.986 | 2020 | 8.177 | 2019 | 8.369 | 2018 | 8.417 | 2017 | 11.455 | 2016 | 10.714 | 2015 | 10.93 | 2014 | 12.401 | 2013 | 12.569 | 2012 | 12.186 | 2011 | 12.998 | 2010 | 11.573 | 2009 | 10.906 | 2008 | 9.845 | 2007 | 10.477 | 2006 | 9.544 | 2005 | 9.837 | 2004 | 9.728 | 2003 | 10.193 | 2002 | 9.61 | 2001 | 9.951 | 2000 | 9.141 | 1999 | 10.1 | 1998 | 9.406 | 1997 | 9.255 | 1996 | 9.394 | 1995 | 9.281 | 1994 | 9.548 | 1993 | 9.655 | 1992 | 10.008 | 1991 | 10.32 | 1990 | 9.915 | 1989 | 9.781 | 1988 | 8.55 | 1987 | 8.613 | 1986 | 8.212 | 1985 | 8.097 | 1984 | 7.488 | 1983 | 6.613 | 1982 | 6.547 | 1981 | 6.329 | 1980 | 6.689 | 1979 | 6.821 | 1978 | 6.974 | 1977 | 7.62 | 1976 | 7.461 | 1975 | 7.346 | 1974 | 7.566 | 1973 | 7.912 | 1972 | 8.366 | 1971 | 9.834 | 1970 | 9.454 | 1969 | 10.423 | 1968 | 9.894 | 1967 | 9.558 | 1966 | 10.552 | 1965 | 9.76 | 1964 | 9.898 | 1963 | 13.344 | 1962 | 11.68 | 1961 | 12.858 | 1960 | 14.029 |
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