| Year | Value | | 2021 | 42.7326171875 | | 2020 | 42.7326171875 | | 2019 | 42.7326171875 | | 2018 | 42.7326171875 | | 2017 | 42.7326171875 | | 2016 | 42.5099609375 | | 2015 | 42.197265625 | | 2014 | 41.971328125 | | 2013 | 41.745390625 | | 2012 | 41.519453125 | | 2011 | 41.293515625 | | 2010 | 41.067578125 | | 2009 | 41.08513671875 | | 2008 | 41.1026953125 | | 2007 | 41.12025390625 | | 2006 | 41.1378125 | | 2005 | 41.15537109375 | | 2004 | 41.1729296875 | | 2003 | 41.19048828125 | | 2002 | 41.208046875 | | 2001 | 41.22560546875 | | 2000 | 41.2431640625 | | 1999 | 41.43525390625 | | 1998 | 41.62734375 | | 1997 | 41.81943359375 | | 1996 | 42.0115234375 | | 1995 | 42.20361328125 | | 1994 | 42.395703125 | | 1993 | 42.58779296875 | | 1992 | 42.7798828125 |
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