Year | Value | 2021 | 11.1 | 2020 | 9.3 | 2019 | 8.8 | 2018 | 8.8 | 2017 | 8.9 | 2016 | 9.3 | 2015 | 8.8 | 2014 | 8.8 | 2013 | 8.1 | 2012 | 8.2 | 2011 | 8.5 | 2010 | 8.4 | 2009 | 7.9 | 2008 | 8.6 | 2007 | 7.9 | 2006 | 8 | 2005 | 8.49 | 2004 | 8.448 | 2003 | 8.379 | 2002 | 8.352 | 2001 | 8.256 | 2000 | 8.084 | 1999 | 7.914 | 1998 | 7.747 | 1997 | 7.617 | 1996 | 7.473 | 1995 | 7.349 | 1994 | 7.204 | 1993 | 7.111 | 1992 | 7.021 | 1991 | 6.932 | 1990 | 6.864 | 1989 | 6.865 | 1988 | 6.729 | 1987 | 6.658 | 1986 | 6.645 | 1985 | 6.586 | 1984 | 6.597 | 1983 | 6.506 | 1982 | 6.446 | 1981 | 6.391 | 1980 | 6.337 | 1979 | 6.292 | 1978 | 6.309 | 1977 | 6.332 | 1976 | 6.28 | 1975 | 6.34 | 1974 | 6.299 | 1973 | 6.366 | 1972 | 6.487 | 1971 | 6.623 | 1970 | 6.707 | 1969 | 6.857 | 1968 | 6.994 | 1967 | 7.08 | 1966 | 7.222 | 1965 | 7.368 | 1964 | 7.494 | 1963 | 7.606 | 1962 | 7.763 | 1961 | 7.93 | 1960 | 8.087 |
|