Year | Value | 2021 | 6.387 | 2020 | 6.294 | 2019 | 5.876 | 2018 | 5.879 | 2017 | 5.863 | 2016 | 6.123 | 2015 | 6.198 | 2014 | 6.345 | 2013 | 6.552 | 2012 | 6.775 | 2011 | 7.145 | 2010 | 7.055 | 2009 | 7.169 | 2008 | 7.26 | 2007 | 7.477 | 2006 | 7.699 | 2005 | 8.083 | 2004 | 8.151 | 2003 | 8.483 | 2002 | 8.817 | 2001 | 9.101 | 2000 | 9.334 | 1999 | 9.522 | 1998 | 9.687 | 1997 | 9.768 | 1996 | 9.887 | 1995 | 9.984 | 1994 | 10.054 | 1993 | 10.093 | 1992 | 10.088 | 1991 | 10.064 | 1990 | 10.105 | 1989 | 10.819 | 1988 | 10.351 | 1987 | 10.596 | 1986 | 12.431 | 1985 | 11.381 | 1984 | 11.634 | 1983 | 11.685 | 1982 | 11.628 | 1981 | 11.545 | 1980 | 11.312 | 1979 | 11.287 | 1978 | 11.434 | 1977 | 11.661 | 1976 | 11.77 | 1975 | 11.924 | 1974 | 12.018 | 1973 | 12.059 | 1972 | 12.394 | 1971 | 12.719 | 1970 | 13.231 | 1969 | 13.902 | 1968 | 13.939 | 1967 | 14.337 | 1966 | 15.745 | 1965 | 17.317 | 1964 | 18.686 | 1963 | 19.647 | 1962 | 20.021 | 1961 | 21.079 | 1960 | 22.169 |
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