Year | Value | 2021 | 8.716 | 2020 | 8.574 | 2019 | 8.206 | 2018 | 8.401 | 2017 | 8.642 | 2016 | 8.898 | 2015 | 9.223 | 2014 | 9.549 | 2013 | 9.819 | 2012 | 10.155 | 2011 | 10.579 | 2010 | 11.035 | 2009 | 11.52 | 2008 | 12.15 | 2007 | 12.55 | 2006 | 13.092 | 2005 | 13.87 | 2004 | 14.077 | 2003 | 14.661 | 2002 | 15.07 | 2001 | 15.553 | 2000 | 15.956 | 1999 | 17.408 | 1998 | 17.779 | 1997 | 17.991 | 1996 | 17.572 | 1995 | 17.914 | 1994 | 18.704 | 1993 | 18.951 | 1992 | 19.479 | 1991 | 20.167 | 1990 | 20.568 | 1989 | 20.996 | 1988 | 21.36 | 1987 | 21.83 | 1986 | 22.155 | 1985 | 22.469 | 1984 | 22.679 | 1983 | 22.796 | 1982 | 22.93 | 1981 | 23.059 | 1980 | 23.165 | 1979 | 23.532 | 1978 | 23.726 | 1977 | 23.584 | 1976 | 23.193 | 1975 | 22.7 | 1974 | 22.154 | 1973 | 24.037 | 1972 | 24.311 | 1971 | 24.559 | 1970 | 24.897 | 1969 | 25.159 | 1968 | 25.612 | 1967 | 26.202 | 1966 | 26.882 | 1965 | 27.523 | 1964 | 28.103 | 1963 | 28.586 | 1962 | 26.707 | 1961 | 27 | 1960 | 27.099 |
|