Year | Value | 2021 | 38.541663268133 | 2020 | 38.524965540636 | 2019 | 38.502300246065 | 2018 | 38.485077510437 | 2017 | 38.469052382511 | 2016 | 38.444426827323 | 2015 | 38.422841832908 | 2014 | 38.407874490042 | 2013 | 38.386352060834 | 2012 | 38.367194590069 | 2011 | 38.346429868296 | 2010 | 38.325236264875 | 2009 | 38.279155779821 | 2008 | 38.232586499514 | 2007 | 38.182750146378 | 2006 | 38.134724602033 | 2005 | 38.100350975428 | 2004 | 38.053926836687 | 2003 | 38.007590542051 | 2002 | 37.961981818008 | 2001 | 37.914693482557 | 2000 | 37.866316310928 | 1999 | 37.858487933396 | 1998 | 37.836074661021 | 1997 | 37.807638315069 | 1996 | 37.87200944831 | 1995 | 37.83961952521 | 1994 | 37.803544740523 | 1993 | 37.764934790869 | 1992 | 37.735098961745 |
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