Year | Value | 2021 | 7.627 | 2020 | 7.448 | 2019 | 7.143 | 2018 | 7.373 | 2017 | 7.39 | 2016 | 7.46 | 2015 | 7.773 | 2014 | 7.817 | 2013 | 8.092 | 2012 | 8.238 | 2011 | 8.417 | 2010 | 8.626 | 2009 | 8.706 | 2008 | 8.905 | 2007 | 9.026 | 2006 | 9.14 | 2005 | 9.247 | 2004 | 9.476 | 2003 | 9.513 | 2002 | 9.744 | 2001 | 9.974 | 2000 | 9.922 | 1999 | 9.962 | 1998 | 10.142 | 1997 | 10.322 | 1996 | 10.513 | 1995 | 10.676 | 1994 | 10.941 | 1993 | 10.865 | 1992 | 11.02 | 1991 | 11.209 | 1990 | 11.492 | 1989 | 11.818 | 1988 | 12.302 | 1987 | 12.799 | 1986 | 13.294 | 1985 | 13.798 | 1984 | 14.157 | 1983 | 14.396 | 1982 | 14.556 | 1981 | 14.808 | 1980 | 15.111 | 1979 | 15.168 | 1978 | 15.349 | 1977 | 15.583 | 1976 | 15.934 | 1975 | 16.421 | 1974 | 16.892 | 1973 | 17.311 | 1972 | 17.76 | 1971 | 18.263 | 1970 | 18.422 | 1969 | 18.649 | 1968 | 18.661 | 1967 | 18.613 | 1966 | 18.621 | 1965 | 18.628 | 1964 | 18.671 | 1963 | 18.733 | 1962 | 18.747 | 1961 | 18.668 | 1960 | 18.998 |
|