Year | Value | 2021 | 33.596 | 2020 | 34.226 | 2019 | 34.823 | 2018 | 35.236 | 2017 | 35.669 | 2016 | 36.038 | 2015 | 36.413 | 2014 | 36.349 | 2013 | 36.327 | 2012 | 36.316 | 2011 | 36.91 | 2010 | 37.497 | 2009 | 37.557 | 2008 | 37.497 | 2007 | 37.121 | 2006 | 36.495 | 2005 | 35.929 | 2004 | 36.338 | 2003 | 36.928 | 2002 | 37.42 | 2001 | 37.9 | 2000 | 38.097 | 1999 | 38.409 | 1998 | 38.608 | 1997 | 39.062 | 1996 | 39.714 | 1995 | 40.284 | 1994 | 40.953 | 1993 | 41.658 | 1992 | 42.219 | 1991 | 42.673 | 1990 | 43.092 | 1989 | 43.782 | 1988 | 44.196 | 1987 | 44.525 | 1986 | 45.188 | 1985 | 45.753 | 1984 | 46.376 | 1983 | 47.006 | 1982 | 47.25 | 1981 | 47.256 | 1980 | 47.292 | 1979 | 47.341 | 1978 | 47.381 | 1977 | 47.24 | 1976 | 47.25 | 1975 | 47.314 | 1974 | 47.362 | 1973 | 47.803 | 1972 | 48.374 | 1971 | 48.884 | 1970 | 48.781 | 1969 | 48.781 | 1968 | 48.721 | 1967 | 48.869 | 1966 | 48.747 | 1965 | 48.513 | 1964 | 48.425 | 1963 | 48.102 | 1962 | 47.735 | 1961 | 47.197 | 1960 | 47.337 |
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