Year | Value | 2021 | 10.181 | 2020 | 10.036 | 2019 | 9.91 | 2018 | 9.83 | 2017 | 9.443 | 2016 | 9.372 | 2015 | 9.763 | 2014 | 9.612 | 2013 | 9.284 | 2012 | 9.146 | 2011 | 9.362 | 2010 | 9.24 | 2009 | 8.936 | 2008 | 8.832 | 2007 | 8.73 | 2006 | 8.65 | 2005 | 8.46 | 2004 | 8.39 | 2003 | 8.697 | 2002 | 8.937 | 2001 | 9.106 | 2000 | 9.249 | 1999 | 9.791 | 1998 | 10.265 | 1997 | 10.195 | 1996 | 10.547 | 1995 | 10.709 | 1994 | 10.796 | 1993 | 10.79 | 1992 | 11.279 | 1991 | 11.82 | 1990 | 12.211 | 1989 | 12.19 | 1988 | 11.856 | 1987 | 11.784 | 1986 | 11.738 | 1985 | 11.532 | 1984 | 11.791 | 1983 | 12.144 | 1982 | 12.371 | 1981 | 12.605 | 1980 | 12.795 | 1979 | 12.555 | 1978 | 12.215 | 1977 | 11.742 | 1976 | 11.57 | 1975 | 11.69 | 1974 | 12.233 | 1973 | 12.845 | 1972 | 12.765 | 1971 | 12.427 | 1970 | 12.066 | 1969 | 12.109 | 1968 | 11.941 | 1967 | 12 | 1966 | 12.222 | 1965 | 12.441 | 1964 | 12.759 | 1963 | 13.068 | 1962 | 14.036 | 1961 | 15.198 | 1960 | 15.244 |
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