| Year | Value | | 2022 | 71.929672139404 | | 2021 | 71.83426868018 | | 2020 | 71.715193732092 | | 2019 | 71.192804222482 | | 2018 | 70.806951803006 | | 2017 | 70.93186899053 | | 2016 | 71.126837348331 | | 2015 | 69.58627409549 | | 2014 | 68.897057289439 | | 2013 | 68.608000349109 | | 2012 | 68.797092655169 | | 2011 | 68.060110858073 | | 2010 | 67.781198356308 | | 2009 | 66.597244908613 | | 2008 | 66.071461082008 | | 2007 | 64.586478661971 | | 2006 | 64.804868336208 | | 2005 | 63.465924090479 | | 2004 | 62.430406123595 | | 2003 | 62.729792224047 | | 2002 | 62.988402777726 | | 2001 | 62.977964527619 | | 2000 | 62.554291519378 | | 1999 | 62.526989105943 | | 1998 | 62.227575799057 | | 1997 | 62.213462459133 | | 1996 | 61.870824862008 | | 1995 | 61.360389230363 | | 1994 | 61.062290036681 | | 1993 | 60.68585463329 | | 1992 | 60.428493456 | | 1991 | 60.156612117467 |
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