| Year | Value | | 2022 | 60.995497187194 | | 2021 | 61.00246381275 | | 2020 | 61.35430518617 | | 2019 | 62.140032420201 | | 2018 | 62.448574030594 | | 2017 | 66.472603226494 | | 2016 | 70.224730565281 | | 2015 | 68.261975194802 | | 2014 | 66.015086542408 | | 2013 | 63.774291996381 | | 2012 | 63.341678905994 | | 2011 | 65.111413883735 | | 2010 | 66.510025917337 | | 2009 | 66.808304760302 | | 2008 | 67.407456535807 | | 2007 | 67.289893862483 | | 2006 | 67.331920660995 | | 2005 | 66.950752952343 | | 2004 | 66.658708104692 | | 2003 | 66.371113910843 | | 2002 | 66.569970781178 | | 2001 | 66.296910214156 | | 2000 | 66.115641053667 | | 1999 | 65.292506014003 | | 1998 | 65.217600049932 | | 1997 | 64.837779652268 | | 1996 | 64.761369425073 | | 1995 | 64.846651183228 | | 1994 | 64.953741778886 | | 1993 | 64.609624434215 | | 1992 | 64.722602712611 | | 1991 | 64.818779650821 |
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