Year | Value | 2021 | 7.776 | 2020 | 7.209 | 2019 | 6.871 | 2018 | 7.041 | 2017 | 6.971 | 2016 | 6.93 | 2015 | 7.376 | 2014 | 6.981 | 2013 | 6.887 | 2012 | 6.961 | 2011 | 6.891 | 2010 | 6.987 | 2009 | 6.897 | 2008 | 6.943 | 2007 | 6.893 | 2006 | 7.014 | 2005 | 7.132 | 2004 | 7.359 | 2003 | 7.587 | 2002 | 7.954 | 2001 | 7.949 | 2000 | 8.294 | 1999 | 8.544 | 1998 | 8.839 | 1997 | 9.252 | 1996 | 9.713 | 1995 | 10.11 | 1994 | 10.547 | 1993 | 11.067 | 1992 | 11.552 | 1991 | 12.131 | 1990 | 12.66 | 1989 | 13.095 | 1988 | 13.739 | 1987 | 14.127 | 1986 | 14.723 | 1985 | 15.17 | 1984 | 15.62 | 1983 | 16.139 | 1982 | 16.481 | 1981 | 16.871 | 1980 | 17.241 | 1979 | 17.708 | 1978 | 18.13 | 1977 | 18.619 | 1976 | 18.953 | 1975 | 19.315 | 1974 | 19.739 | 1973 | 20.073 | 1972 | 20.425 | 1971 | 20.77 | 1970 | 21.186 | 1969 | 21.615 | 1968 | 22.076 | 1967 | 22.407 | 1966 | 22.872 | 1965 | 23.257 | 1964 | 23.665 | 1963 | 24.124 | 1962 | 24.389 | 1961 | 24.627 | 1960 | 24.851 |
|