Year | Value | 2021 | 36.841665495843 | 2020 | 36.73092028654 | 2019 | 36.762647759981 | 2018 | 36.738458065713 | 2017 | 36.834000840598 | 2016 | 36.587014153698 | 2015 | 36.620495521649 | 2014 | 36.789050992635 | 2013 | 36.790232476396 | 2012 | 36.867752999981 | 2011 | 36.949918753407 | 2010 | 36.805434007783 | 2009 | 36.810781713722 | 2008 | 36.855935427847 | 2007 | 36.9729180055 | 2006 | 37.037442160419 | 2005 | 37.026446786984 | 2004 | 36.970535038878 | 2003 | 37.331860075479 | 2002 | 37.475004050778 | 2001 | 37.535860187606 | 2000 | 37.520184107567 | 1999 | 37.496551410495 | 1998 | 37.475908137717 | 1997 | 37.364906957681 | 1996 | 37.228742182179 | 1995 | 37.167201844115 | 1994 | 37.176222754802 | 1993 | 37.001242512308 | 1992 | 37.113465035489 | 1991 | 38.973289515634 | 1990 | 38.929947843294 | 1989 | 38.816107470662 | 1988 | 38.711165642725 | 1987 | 38.552444525824 | 1986 | 38.387631507192 | 1985 | 38.401788827442 | 1984 | 38.138917248577 | 1983 | 37.893134717811 | 1982 | 37.825206718534 | 1981 | 37.703888270367 | 1980 | 37.654271396871 | 1979 | 37.532416659843 | 1978 | 37.454499023927 | 1977 | 37.289662532293 | 1976 | 37.242945539181 | 1975 | 37.242388525921 | 1974 | 37.146785797877 | 1973 | 37.024645175556 | 1972 | 36.931241310682 | 1971 | 36.797793691703 | 1970 | 36.650371582575 | 1969 | 36.742753595134 | 1968 | 36.70157932771 | 1967 | 36.389050836518 | 1966 | 36.294320909967 | 1965 | 36.213940933646 | 1964 | 36.117042825146 | 1963 | 36.035383414266 | 1962 | 35.952470262616 | 1961 | 35.879316704738 |
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