Year | Value | 2021 | 9.1 | 2020 | 8.9 | 2019 | 9.3 | 2018 | 9.2 | 2017 | 9.2 | 2016 | 9.2 | 2015 | 9.3 | 2014 | 9.3 | 2013 | 9.2 | 2012 | 9.3 | 2011 | 9.1 | 2010 | 9.4 | 2009 | 9.6 | 2008 | 9.4 | 2007 | 9.22 | 2006 | 9.58 | 2005 | 9.7 | 2004 | 10.5 | 2003 | 10.6 | 2002 | 10.4 | 2001 | 10.5 | 2000 | 9.8 | 1999 | 9.6 | 1998 | 10.09 | 1997 | 10.49 | 1996 | 10.8 | 1995 | 11.3 | 1994 | 11.338 | 1993 | 11.638 | 1992 | 11.51 | 1991 | 11.932 | 1990 | 12.1 | 1989 | 12.128 | 1988 | 12.933 | 1987 | 13.077 | 1986 | 13.111 | 1985 | 13.397 | 1984 | 13.987 | 1983 | 13.641 | 1982 | 13.866 | 1981 | 13.438 | 1980 | 14.484 | 1979 | 14.402 | 1978 | 14.898 | 1977 | 15.157 | 1976 | 15.585 | 1975 | 15.599 | 1974 | 15.485 | 1973 | 15.402 | 1972 | 15.433 | 1971 | 14.723 | 1970 | 15.391 | 1969 | 16.224 | 1968 | 16.339 | 1967 | 16.63 | 1966 | 16.867 | 1965 | 17.452 | 1964 | 17.093 | 1963 | 17.579 | 1962 | 17.685 | 1961 | 18.424 | 1960 | 18.934 |
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