Year | Value | 2021 | 7.317 | 2020 | 6.169 | 2019 | 6.706 | 2018 | 6.663 | 2017 | 6.577 | 2016 | 6.495 | 2015 | 6.444 | 2014 | 6.373 | 2013 | 6.327 | 2012 | 6.275 | 2011 | 6.195 | 2010 | 6.193 | 2009 | 6.117 | 2008 | 6.066 | 2007 | 5.966 | 2006 | 5.927 | 2005 | 5.865 | 2004 | 5.835 | 2003 | 5.812 | 2002 | 5.8 | 2001 | 5.769 | 2000 | 5.755 | 1999 | 5.729 | 1998 | 5.753 | 1997 | 5.817 | 1996 | 5.893 | 1995 | 5.924 | 1994 | 6.173 | 1993 | 6.228 | 1992 | 6.504 | 1991 | 6.549 | 1990 | 6.816 | 1989 | 6.875 | 1988 | 7.142 | 1987 | 7.19 | 1986 | 7.358 | 1985 | 7.554 | 1984 | 7.685 | 1983 | 7.754 | 1982 | 7.763 | 1981 | 7.954 | 1980 | 8.122 | 1979 | 8.157 | 1978 | 8.339 | 1977 | 8.534 | 1976 | 8.649 | 1975 | 9.48 | 1974 | 13 | 1973 | 12.523 | 1972 | 14.57 | 1971 | 12.508 | 1970 | 12.773 | 1969 | 12.817 | 1968 | 14.001 | 1967 | 11.792 | 1966 | 11.701 | 1965 | 11.676 | 1964 | 11.437 | 1963 | 11.813 | 1962 | 11.054 | 1961 | 10.9 | 1960 | 11.467 |
|