Year | Value | 2021 | 7.1 | 2020 | 7.2 | 2019 | 7.6 | 2018 | 7.9 | 2017 | 8.4 | 2016 | 8.8 | 2015 | 9 | 2014 | 9.2 | 2013 | 9.1 | 2012 | 9.7 | 2011 | 10.1 | 2010 | 10.4 | 2009 | 10.6 | 2008 | 11.3 | 2007 | 10.9 | 2006 | 10.8 | 2005 | 10.6 | 2004 | 10.6 | 2003 | 10.4 | 2002 | 10.1 | 2001 | 9.9 | 2000 | 9.8 | 1999 | 9.4 | 1998 | 9.1 | 1997 | 9.2 | 1996 | 9.1 | 1995 | 9.1 | 1994 | 9.4 | 1993 | 9.8 | 1992 | 10.1 | 1991 | 10.2 | 1990 | 10.3 | 1989 | 10.5 | 1988 | 10.8 | 1987 | 11 | 1986 | 11.4 | 1985 | 11.9 | 1984 | 12.3 | 1983 | 12.7 | 1982 | 13.6 | 1981 | 14.1 | 1980 | 15.2 | 1979 | 16.2 | 1978 | 17.3 | 1977 | 18 | 1976 | 18.7 | 1975 | 18.7 | 1974 | 19.5 | 1973 | 19.2 | 1972 | 19.4 | 1971 | 19.6 | 1970 | 19.5 | 1969 | 19.9 | 1968 | 20.1 | 1967 | 20.7 | 1966 | 20.7 | 1965 | 21.1 | 1964 | 22 | 1963 | 21.4 | 1962 | 21.1 | 1961 | 21.2 | 1960 | 21.7 |
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