Year | Value | 2021 | 37.326147426982 | 2020 | 36.86978442281 | 2019 | 38.969054242003 | 2018 | 37.752086230876 | 2017 | 37.130563282337 | 2016 | 37.300069541029 | 2015 | 38.151947148818 | 2014 | 38.151947148818 | 2013 | 38.021127678998 | 2012 | 38.248847926267 | 2011 | 39.079810574793 | 2010 | 39.756574657683 | 2009 | 38.203077458054 | 2008 | 37.933884297521 | 2007 | 37.735438688068 | 2006 | 38.868597269328 | 2005 | 39.068614662144 | 2004 | 38.760869565217 | 2003 | 40.778430093499 | 2002 | 40.788271631792 | 2001 | 40.794915328022 | 2000 | 40.838448478516 | 1999 | 40.644599303136 | 1998 | 40.615880482599 | 1997 | 40.717988933908 | 1996 | 40.680550714535 | 1995 | 40.685868665301 | 1994 | 40.691037427563 | 1993 | 40.708620238822 | 1992 | 40.778349167611 | 1991 | 41.065980998867 | 1990 | 41.203400915631 | 1989 | 41.238282101592 | 1988 | 43.878614222454 | 1987 | 43.761396196926 | 1986 | 43.435790570461 | 1985 | 43.348962403404 | 1984 | 43.13189198576 | 1983 | 42.997308326821 | 1982 | 42.849700442824 | 1981 | 42.758530867413 | 1980 | 42.69340974212 | 1979 | 42.619605800122 | 1978 | 42.558826083181 | 1977 | 42.463315099418 | 1976 | 42.372145524008 | 1975 | 42.289658765303 | 1974 | 42.124685247894 |
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