Year | Value | 2021 | 12.125 | 2020 | 12.418 | 2019 | 12.693 | 2018 | 12.942 | 2017 | 13.211 | 2016 | 13.456 | 2015 | 13.583 | 2014 | 13.8 | 2013 | 13.975 | 2012 | 14.268 | 2011 | 14.53 | 2010 | 14.789 | 2009 | 15.172 | 2008 | 15.485 | 2007 | 15.804 | 2006 | 16.046 | 2005 | 16.253 | 2004 | 16.467 | 2003 | 16.732 | 2002 | 16.953 | 2001 | 17.386 | 2000 | 18.436 | 1999 | 19.625 | 1998 | 20.132 | 1997 | 20.368 | 1996 | 19.859 | 1995 | 20.17 | 1994 | 20.055 | 1993 | 20.429 | 1992 | 20.706 | 1991 | 22.185 | 1990 | 23.939 | 1989 | 24.172 | 1988 | 24.185 | 1987 | 24.622 | 1986 | 25.554 | 1985 | 26.832 | 1984 | 27.238 | 1983 | 28.692 | 1982 | 29.93 | 1981 | 28.813 | 1980 | 27.931 | 1979 | 27.602 | 1978 | 28.009 | 1977 | 29.24 | 1976 | 29.603 | 1975 | 29.174 | 1974 | 28.547 | 1973 | 27.743 | 1972 | 27.107 | 1971 | 27.234 | 1970 | 26.881 | 1969 | 28.391 | 1968 | 30.13 | 1967 | 32.774 | 1966 | 35.75 | 1965 | 38.018 | 1964 | 39.553 | 1963 | 40.748 | 1962 | 41.147 | 1961 | 43.239 | 1960 | 45.231 |
|