| Year | Value | | 2021 | 42.911044826638 | | 2020 | 43.02951069366 | | 2019 | 43.147976560682 | | 2018 | 43.266442427704 | | 2017 | 43.384908294726 | | 2016 | 43.503374161748 | | 2015 | 43.62184002877 | | 2014 | 43.740305895792 | | 2013 | 43.858771762814 | | 2012 | 43.977237629837 | | 2011 | 44.095703496858 | | 2010 | 44.214169363881 | | 2009 | 44.361619174547 | | 2008 | 44.509068985213 | | 2007 | 44.656518795879 | | 2006 | 44.803968606545 | | 2005 | 44.951418417211 | | 2004 | 45.098868227878 | | 2003 | 45.246318038544 | | 2002 | 45.39376784921 | | 2001 | 45.541217659876 | | 2000 | 45.688667470542 | | 1999 | 45.879590023482 | | 1998 | 46.070512576421 | | 1997 | 46.26143512936 | | 1996 | 46.4523576823 | | 1995 | 46.643280235239 | | 1994 | 46.834202788179 | | 1993 | 47.025125341118 | | 1992 | 47.216047894058 | | 1991 | 47.406970446997 | | 1990 | 47.597892999936 |
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