Year | Value | 2021 | 56.741517613813 | 2020 | 56.80028154428 | 2019 | 56.749445722535 | 2018 | 56.845034636416 | 2017 | 56.834719276535 | 2016 | 56.852554328925 | 2015 | 56.730998945521 | 2014 | 56.718928128944 | 2013 | 56.708448029291 | 2012 | 56.619576784232 | 2011 | 56.599266351104 | 2010 | 56.434477264157 | 2009 | 56.547264096625 | 2008 | 56.490734439096 | 2007 | 56.57975240555 | 2006 | 56.684763004074 | 2005 | 56.725216188736 | 2004 | 56.758962109619 | 2003 | 56.885826053979 | 2002 | 56.944703444432 | 2001 | 56.961465690825 | 2000 | 57.002763675374 | 1999 | 57.035337406858 | 1998 | 57.010569371453 | 1997 | 56.981610467114 | 1996 | 56.776425524068 | 1995 | 56.827931303276 | 1994 | 56.843395609646 | 1993 | 56.811648302029 | 1992 | 56.762225835563 | 1991 | 56.956567862884 | 1990 | 56.911246498632 | 1989 | 57.077466682206 | 1988 | 56.881492583596 | 1987 | 57.188531225813 | 1986 | 56.864711542908 | 1985 | 57.210878048076 | 1984 | 57.319766496631 | 1983 | 56.859940872987 | 1982 | 57.361154150598 | 1981 | 56.873708858988 | 1980 | 57.03419586906 | 1979 | 56.869314820902 | 1978 | 56.908442683853 | 1977 | 56.583702345349 | 1976 | 56.543946762672 | 1975 | 56.609920105926 | 1974 | 56.4552918133 | 1973 | 56.470754642563 | 1972 | 56.08633908206 | 1971 | 55.963724495486 | 1970 | 56.085083642607 | 1969 | 55.95765653813 | 1968 | 56.378856474605 | 1967 | 56.316084501956 | 1966 | 56.21878794435 | 1965 | 56.084455922881 | 1964 | 55.76620202155 | 1963 | 55.522856007581 | 1962 | 55.496073299251 | 1961 | 55.146014931778 |
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