| Year | Value | | 2021 | 44.19921875 | | 2020 | 43.7890625 | | 2019 | 43.28125 | | 2018 | 43.18359375 | | 2017 | 43.515625 | | 2016 | 43.14453125 | | 2015 | 42.5 | | 2014 | 42.12890625 | | 2013 | 42.20703125 | | 2012 | 42.109375 | | 2011 | 42.01171875 | | 2010 | 41.875 | | 2009 | 41.5625 | | 2008 | 41.6015625 | | 2007 | 41.97265625 | | 2006 | 42.16796875 | | 2005 | 42.12890625 | | 2004 | 42.37109375 | | 2003 | 42.36328125 | | 2002 | 41.46484375 | | 2001 | 41.5234375 | | 2000 | 41.6015625 | | 1999 | 41.11328125 | | 1998 | 42.1875 | | 1997 | 42.28515625 | | 1996 | 42.3828125 | | 1995 | 42.48046875 | | 1994 | 42.578125 | | 1993 | 42.7734375 | | 1992 | 42.96875 |
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