Year | Value | 2021 | 7.543 | 2020 | 7.373 | 2019 | 6.999 | 2018 | 7.323 | 2017 | 7.396 | 2016 | 7.454 | 2015 | 7.74 | 2014 | 7.916 | 2013 | 8.073 | 2012 | 8.174 | 2011 | 8.501 | 2010 | 8.941 | 2009 | 9.171 | 2008 | 9.432 | 2007 | 9.856 | 2006 | 10.132 | 2005 | 10.56 | 2004 | 10.847 | 2003 | 11.237 | 2002 | 11.57 | 2001 | 11.69 | 2000 | 11.841 | 1999 | 12.024 | 1998 | 12.254 | 1997 | 12.607 | 1996 | 12.751 | 1995 | 13.163 | 1994 | 13.712 | 1993 | 14.408 | 1992 | 14.983 | 1991 | 15.541 | 1990 | 16.102 | 1989 | 16.608 | 1988 | 17.061 | 1987 | 17.558 | 1986 | 18.115 | 1985 | 18.565 | 1984 | 19.148 | 1983 | 19.489 | 1982 | 19.826 | 1981 | 20.99 | 1980 | 20.555 | 1979 | 20.907 | 1978 | 21.542 | 1977 | 21.56 | 1976 | 21.761 | 1975 | 22.1 | 1974 | 22.353 | 1973 | 22.821 | 1972 | 23.222 | 1971 | 23.722 | 1970 | 24.168 | 1969 | 24.661 | 1968 | 25.135 | 1967 | 25.594 | 1966 | 26.139 | 1965 | 26.629 | 1964 | 27.143 | 1963 | 27.604 | 1962 | 28.097 | 1961 | 28.5 | 1960 | 28.943 |
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