Year | Value | 2021 | 31.856 | 2020 | 32.302 | 2019 | 32.756 | 2018 | 33.186 | 2017 | 33.656 | 2016 | 34.099 | 2015 | 34.392 | 2014 | 34.827 | 2013 | 35.308 | 2012 | 35.846 | 2011 | 36.632 | 2010 | 37.351 | 2009 | 37.478 | 2008 | 37.561 | 2007 | 37.822 | 2006 | 37.603 | 2005 | 37.581 | 2004 | 37.659 | 2003 | 38.15 | 2002 | 38.421 | 2001 | 38.562 | 2000 | 38.668 | 1999 | 38.84 | 1998 | 38.826 | 1997 | 38.847 | 1996 | 39.262 | 1995 | 39.717 | 1994 | 40.27 | 1993 | 40.655 | 1992 | 41.104 | 1991 | 41.57 | 1990 | 41.943 | 1989 | 42.301 | 1988 | 42.768 | 1987 | 43.219 | 1986 | 43.505 | 1985 | 43.84 | 1984 | 44.269 | 1983 | 44.667 | 1982 | 45.081 | 1981 | 45.572 | 1980 | 45.927 | 1979 | 46.382 | 1978 | 46.856 | 1977 | 47.229 | 1976 | 47.529 | 1975 | 47.59 | 1974 | 47.725 | 1973 | 47.776 | 1972 | 47.855 | 1971 | 47.879 | 1970 | 47.893 | 1969 | 47.96 | 1968 | 47.823 | 1967 | 47.932 | 1966 | 48.033 | 1965 | 47.943 | 1964 | 47.874 | 1963 | 47.854 | 1962 | 47.616 | 1961 | 47.366 | 1960 | 47.235 |
|