Year | Value | 2022 | 7.1 | 2021 | 6.9 | 2020 | 8.2 | 2019 | 6.8 | 2018 | 7.2 | 2017 | 6.6 | 2016 | 7.2 | 2015 | 6.7 | 2014 | 7.2 | 2013 | 6.7 | 2012 | 6.1 | 2011 | 6.8 | 2010 | 6.6 | 2009 | 6.4 | 2008 | 5.8 | 2007 | 6.4 | 2006 | 6.3 | 2005 | 6.2 | 2004 | 5.7 | 2003 | 6.4 | 2002 | 6.4 | 2001 | 6.6 | 2000 | 7.3 | 1999 | 6.4 | 1998 | 6.6 | 1997 | 7.4 | 1996 | 7.4 | 1995 | 7.3 | 1994 | 6.8 | 1993 | 5.9 | 1992 | 6.1 | 1991 | 6.4 | 1990 | 6.8 | 1989 | 6.1 | 1988 | 7 | 1987 | 6.5 | 1986 | 6.9 | 1985 | 6.4 | 1984 | 6.7 | 1983 | 5.7 | 1982 | 6.4 | 1981 | 6.3 | 1980 | 6.9 | 1979 | 6.8 | 1978 | 6.5 | 1977 | 6.1 | 1976 | 7.4 | 1975 | 7.5 | 1974 | 6.3 |
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