Year | Value | 2021 | 6.973 | 2020 | 6.602 | 2019 | 6.571 | 2018 | 6.748 | 2017 | 6.809 | 2016 | 6.941 | 2015 | 7.196 | 2014 | 7.408 | 2013 | 7.788 | 2012 | 8.267 | 2011 | 8.763 | 2010 | 9.219 | 2009 | 9.961 | 2008 | 10.67 | 2007 | 11.351 | 2006 | 11.933 | 2005 | 12.659 | 2004 | 13.45 | 2003 | 14.32 | 2002 | 15.292 | 2001 | 16.145 | 2000 | 16.876 | 1999 | 17.4 | 1998 | 17.509 | 1997 | 17.511 | 1996 | 17.483 | 1995 | 17.434 | 1994 | 17.392 | 1993 | 17.315 | 1992 | 17.243 | 1991 | 17.001 | 1990 | 16.597 | 1989 | 16.239 | 1988 | 15.836 | 1987 | 15.438 | 1986 | 15.053 | 1985 | 14.602 | 1984 | 14.157 | 1983 | 13.828 | 1982 | 13.614 | 1981 | 13.533 | 1980 | 13.52 | 1979 | 13.436 | 1978 | 13.394 | 1977 | 13.371 | 1976 | 13.444 | 1975 | 13.656 | 1974 | 13.909 | 1973 | 14.302 | 1972 | 14.751 | 1971 | 15.171 | 1970 | 15.527 | 1969 | 15.775 | 1968 | 15.975 | 1967 | 16.042 | 1966 | 16.14 | 1965 | 16.234 | 1964 | 16.685 | 1963 | 16.558 | 1962 | 16.789 | 1961 | 17.019 | 1960 | 17.285 |
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