| Year | Value | | 2021 | 40.275930032028 | | 2020 | 40.797122869248 | | 2019 | 41.322395486907 | | 2018 | 41.644496994778 | | 2017 | 41.84483811851 | | 2016 | 42.035489782647 | | 2015 | 42.242016376159 | | 2014 | 42.487917112128 | | 2013 | 42.931772034617 | | 2012 | 43.351618292845 | | 2011 | 43.73860332167 | | 2010 | 43.853683058817 | | 2009 | 43.997476564579 | | 2008 | 43.947324324058 | | 2007 | 43.942612407036 | | 2006 | 44.148957142294 | | 2005 | 44.12003963852 | | 2004 | 44.163400142987 | | 2003 | 44.303984696242 | | 2002 | 44.495609602177 | | 2001 | 45.000098597937 | | 2000 | 45.61050638902 | | 1999 | 45.75640298765 | | 1998 | 45.885943331575 | | 1997 | 45.875132483794 | | 1996 | 46.008459285989 | | 1995 | 46.034860106079 | | 1994 | 46.067094510001 | | 1993 | 46.103345622301 | | 1992 | 46.277497437515 |
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