| Year | Value | | 2022 | 65.592932811888 | | 2021 | 65.354961657747 | | 2020 | 65.16728373717 | | 2019 | 65.664535768645 | | 2018 | 65.535297408887 | | 2017 | 65.226453065535 | | 2016 | 64.701631673713 | | 2015 | 64.215262778978 | | 2014 | 63.806130007407 | | 2013 | 63.376259820888 | | 2012 | 62.840774954577 | | 2011 | 62.247931747673 | | 2010 | 61.746730179235 | | 2009 | 61.315475422526 | | 2008 | 60.988676537576 | | 2007 | 60.643697282194 | | 2006 | 60.372470684428 | | 2005 | 60.531534619528 | | 2004 | 60.801663877129 | | 2003 | 60.798482223872 | | 2002 | 60.819301644067 | | 2001 | 60.675504712297 | | 2000 | 60.513014235796 | | 1999 | 60.534710494326 | | 1998 | 60.305776912626 | | 1997 | 60.081344071718 | | 1996 | 59.684945852576 | | 1995 | 59.28615704545 | | 1994 | 58.948766209944 | | 1993 | 58.603307431759 | | 1992 | 58.344259980231 | | 1991 | 58.250258311927 |
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