2017 26.7295890410959
2016 27.0688524590164
2015 27.8205479452055
2014 27.3241095890411
2013 27.3054794520548
2012 27.4112021857923
2011 27.8786301369863
2010 29.0884931506849
2009 28.396632996633
2008 28.5449511400651
2007 27.7929203539823
2006 27.5635616438356
2005 27.730659025788
2004 27.4224137931034
2003 27.8841216216216
2002 27.3834459459459
2001 27.3263665594855