| Year | Value | | 2021 | 39.710150674068 | | 2020 | 39.710150674068 | | 2019 | 39.710150674068 | | 2018 | 39.710150674068 | | 2017 | 39.710150674068 | | 2016 | 39.717287866772 | | 2015 | 39.429024583664 | | 2014 | 39.159635210151 | | 2013 | 38.890245836638 | | 2012 | 38.620856463124 | | 2011 | 38.351467089611 | | 2010 | 38.082077716098 | | 2009 | 38.070658207772 | | 2008 | 38.044153785176 | | 2007 | 38.032738803012 | | 2006 | 37.722296500197 | | 2005 | 37.710971293747 | | 2004 | 37.699646087298 | | 2003 | 37.688320880849 | | 2002 | 37.6769956744 | | 2001 | 37.665670467951 | | 2000 | 37.654345261502 | | 1999 | 37.475226110893 | | 1998 | 37.296106960283 | | 1997 | 37.116987809674 | | 1996 | 36.937868659064 | | 1995 | 36.758749508455 | | 1994 | 36.579630357845 | | 1993 | 36.400511207236 | | 1992 | 36.221392056626 |
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