Year | Value | 2021 | 7.063 | 2020 | 6.923 | 2019 | 7.388 | 2018 | 6.797 | 2017 | 6.924 | 2016 | 7.02 | 2015 | 7.196 | 2014 | 7.358 | 2013 | 7.532 | 2012 | 7.753 | 2011 | 7.942 | 2010 | 8.123 | 2009 | 8.377 | 2008 | 8.689 | 2007 | 9.059 | 2006 | 9.439 | 2005 | 9.831 | 2004 | 10.416 | 2003 | 10.973 | 2002 | 11.463 | 2001 | 11.84 | 2000 | 12.204 | 1999 | 12.746 | 1998 | 13.847 | 1997 | 16.201 | 1996 | 12.387 | 1995 | 12.287 | 1994 | 12.225 | 1993 | 12.006 | 1992 | 11.741 | 1991 | 11.459 | 1990 | 11.146 | 1989 | 10.895 | 1988 | 10.698 | 1987 | 10.545 | 1986 | 10.531 | 1985 | 10.59 | 1984 | 10.643 | 1983 | 10.854 | 1982 | 11.056 | 1981 | 11.245 | 1980 | 11.456 | 1979 | 11.697 | 1978 | 11.923 | 1977 | 12.151 | 1976 | 12.341 | 1975 | 12.556 | 1974 | 12.769 | 1973 | 13.031 | 1972 | 13.283 | 1971 | 13.502 | 1970 | 13.77 | 1969 | 14.061 | 1968 | 14.376 | 1967 | 14.776 | 1966 | 15.004 | 1965 | 15.377 | 1964 | 15.714 | 1963 | 16.103 | 1962 | 16.528 | 1961 | 17.09 | 1960 | 17.613 |
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