Year | Value | 2021 | 4.548 | 2020 | 6.121 | 2019 | 4.843 | 2018 | 5.014 | 2017 | 5.172 | 2016 | 5.325 | 2015 | 5.43 | 2014 | 5.512 | 2013 | 5.563 | 2012 | 5.7 | 2011 | 5.808 | 2010 | 5.934 | 2009 | 5.75 | 2008 | 5.816 | 2007 | 5.936 | 2006 | 5.958 | 2005 | 6.116 | 2004 | 6.289 | 2003 | 6.476 | 2002 | 6.795 | 2001 | 7.161 | 2000 | 7.54 | 1999 | 7.882 | 1998 | 8.448 | 1997 | 9.058 | 1996 | 9.858 | 1995 | 10.013 | 1994 | 11.096 | 1993 | 13.525 | 1992 | 12.63 | 1991 | 9.804 | 1990 | 9.681 | 1989 | 9.743 | 1988 | 9.859 | 1987 | 10.121 | 1986 | 10.269 | 1985 | 10.375 | 1984 | 10.558 | 1983 | 10.716 | 1982 | 10.788 | 1981 | 10.924 | 1980 | 10.911 | 1979 | 10.866 | 1978 | 10.904 | 1977 | 10.996 | 1976 | 11.139 | 1975 | 11.334 | 1974 | 11.614 | 1973 | 11.972 | 1972 | 12.255 | 1971 | 12.6 | 1970 | 12.953 | 1969 | 13.262 | 1968 | 13.65 | 1967 | 14.057 | 1966 | 14.47 | 1965 | 14.869 | 1964 | 15.27 | 1963 | 15.69 | 1962 | 16.056 | 1961 | 16.341 | 1960 | 16.625 |
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