Year | Value | 2021 | 27.142 | 2020 | 27.695 | 2019 | 28.354 | 2018 | 29.004 | 2017 | 29.713 | 2016 | 30.362 | 2015 | 31.036 | 2014 | 31.622 | 2013 | 32.182 | 2012 | 32.718 | 2011 | 33.223 | 2010 | 33.177 | 2009 | 32.96 | 2008 | 32.675 | 2007 | 32.685 | 2006 | 32.68 | 2005 | 32.722 | 2004 | 32.771 | 2003 | 32.884 | 2002 | 33.101 | 2001 | 33.279 | 2000 | 33.471 | 1999 | 33.502 | 1998 | 33.777 | 1997 | 33.992 | 1996 | 34.248 | 1995 | 34.82 | 1994 | 35.578 | 1993 | 36.378 | 1992 | 36.839 | 1991 | 37.222 | 1990 | 37.635 | 1989 | 38.056 | 1988 | 38.495 | 1987 | 38.675 | 1986 | 38.686 | 1985 | 38.8 | 1984 | 38.902 | 1983 | 39.025 | 1982 | 38.933 | 1981 | 38.884 | 1980 | 38.527 | 1979 | 38.205 | 1978 | 38.026 | 1977 | 37.66 | 1976 | 37.27 | 1975 | 36.873 | 1974 | 36.499 | 1973 | 36.292 | 1972 | 36.018 | 1971 | 35.574 | 1970 | 35.13 | 1969 | 34.746 | 1968 | 34.421 | 1967 | 34.095 | 1966 | 33.841 | 1965 | 33.48 | 1964 | 33.144 | 1963 | 32.88 | 1962 | 32.634 | 1961 | 32.254 | 1960 | 31.893 |
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