| Year | Value | | 2022 | 72.848345806214 | | 2021 | 72.502806655575 | | 2020 | 72.184373654719 | | 2019 | 72.176783262104 | | 2018 | 71.502129913335 | | 2017 | 70.634069745683 | | 2016 | 69.915470595299 | | 2015 | 69.018108345916 | | 2014 | 68.209435137081 | | 2013 | 67.498649822598 | | 2012 | 66.744554837624 | | 2011 | 66.082519976297 | | 2010 | 65.586599217229 | | 2009 | 64.950343739332 | | 2008 | 66.079938459863 | | 2007 | 66.742657834263 | | 2006 | 66.231950080622 | | 2005 | 65.698401557162 | | 2004 | 65.310543933159 | | 2003 | 64.864758869388 | | 2002 | 64.432871500982 | | 2001 | 64.054525886828 | | 2000 | 63.698058883014 | | 1999 | 63.643745695088 | | 1998 | 63.620823414427 | | 1997 | 63.846586616267 | | 1996 | 64.255291167857 | | 1995 | 64.772877182182 | | 1994 | 65.103061633226 | | 1993 | 65.605458249089 | | 1992 | 65.863806802251 | | 1991 | 66.024492223232 |
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