Year | Value | 2021 | 9.61 | 2020 | 8.6 | 2019 | 7.19 | 2018 | 7.14 | 2017 | 7.15 | 2016 | 7.37 | 2015 | 7.46 | 2014 | 7.65 | 2013 | 8 | 2012 | 8.54 | 2011 | 8.72 | 2010 | 8.95 | 2009 | 8.88 | 2008 | 9.74 | 2007 | 10.22 | 2006 | 10.27 | 2005 | 10.37 | 2004 | 10.14 | 2003 | 10.41 | 2002 | 10.05 | 2001 | 9.95 | 2000 | 10.06 | 1999 | 9.87 | 1998 | 10.24 | 1997 | 10.44 | 1996 | 10.66 | 1995 | 10.66 | 1994 | 9.93 | 1993 | 9.53 | 1992 | 8.37 | 1991 | 8.19 | 1990 | 7.87 | 1989 | 7.6 | 1988 | 7.7 | 1987 | 7.6 | 1986 | 7.4 | 1985 | 8 | 1984 | 8.3 | 1983 | 8 | 1982 | 7.9 | 1981 | 8 | 1980 | 8 | 1979 | 7.7 | 1978 | 9.888 | 1977 | 9.957 | 1976 | 10.022 | 1975 | 9.844 | 1974 | 9.939 | 1973 | 10.026 | 1972 | 10.127 | 1971 | 10.252 | 1970 | 10.332 | 1969 | 10.445 | 1968 | 10.6 | 1967 | 10.749 | 1966 | 10.94 | 1965 | 11.203 | 1964 | 11.561 | 1963 | 11.885 | 1962 | 12.281 | 1961 | 12.538 | 1960 | 12.763 |
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