Year | Value | 2021 | 28.624 | 2020 | 28.706 | 2019 | 28.941 | 2018 | 29.105 | 2017 | 29.421 | 2016 | 29.91 | 2015 | 30.417 | 2014 | 31.214 | 2013 | 31.719 | 2012 | 32.424 | 2011 | 33.114 | 2010 | 33.692 | 2009 | 34.402 | 2008 | 34.667 | 2007 | 35.301 | 2006 | 36.24 | 2005 | 36.677 | 2004 | 37.272 | 2003 | 36.8 | 2002 | 37.239 | 2001 | 36.827 | 2000 | 37.617 | 1999 | 38.19 | 1998 | 39.359 | 1997 | 40.646 | 1996 | 42.342 | 1995 | 40.561 | 1994 | 41.484 | 1993 | 40.914 | 1992 | 41.697 | 1991 | 42.003 | 1990 | 42.662 | 1989 | 43.213 | 1988 | 43.635 | 1987 | 43.754 | 1986 | 44.052 | 1985 | 44.35 | 1984 | 44.651 | 1983 | 44.989 | 1982 | 44.984 | 1981 | 44.979 | 1980 | 44.967 | 1979 | 45.073 | 1978 | 45.266 | 1977 | 45.546 | 1976 | 45.771 | 1975 | 45.868 | 1974 | 45.959 | 1973 | 46.029 | 1972 | 46.307 | 1971 | 46.682 | 1970 | 47.028 | 1969 | 47.103 | 1968 | 47.412 | 1967 | 47.652 | 1966 | 47.818 | 1965 | 47.913 | 1964 | 47.921 | 1963 | 47.873 | 1962 | 47.89 | 1961 | 47.644 | 1960 | 47.554 |
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