Year | Value | 2021 | 15.712 | 2020 | 14.094 | 2019 | 12.266 | 2018 | 12.056 | 2017 | 11.842 | 2016 | 11.613 | 2015 | 12.011 | 2014 | 12.276 | 2013 | 11.055 | 2012 | 9.888 | 2011 | 9.851 | 2010 | 9.499 | 2009 | 9.29 | 2008 | 9.103 | 2007 | 9.383 | 2006 | 8.901 | 2005 | 9.242 | 2004 | 8.258 | 2003 | 8.187 | 2002 | 8.859 | 2001 | 8.187 | 2000 | 8.358 | 1999 | 7.683 | 1998 | 8.33 | 1997 | 8.314 | 1996 | 8.425 | 1995 | 9.709 | 1994 | 10.635 | 1993 | 19.58 | 1992 | 19.114 | 1991 | 7.769 | 1990 | 7.378 | 1989 | 7.596 | 1988 | 7.463 | 1987 | 7.363 | 1986 | 7.473 | 1985 | 7.61 | 1984 | 7.286 | 1983 | 7.076 | 1982 | 7.018 | 1981 | 6.926 | 1980 | 6.817 | 1979 | 6.739 | 1978 | 6.669 | 1977 | 6.54 | 1976 | 6.569 | 1975 | 6.518 | 1974 | 6.618 | 1973 | 6.778 | 1972 | 6.892 | 1971 | 6.991 | 1970 | 7.082 | 1969 | 7.204 | 1968 | 7.261 | 1967 | 7.35 | 1966 | 7.49 | 1965 | 7.759 | 1964 | 8.037 | 1963 | 8.369 | 1962 | 8.758 | 1961 | 9.105 | 1960 | 9.535 |
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