2017 24.3161643835616
2016 24.5494535519126
2015 24.5747945205479
2014 24.3282191780822
2013 24.1602739726027
2012 24.2256830601093
2011 23.9857534246575
2010 24.5731506849315
2009 24.1284931506849
2008 23.7565573770492
2007 24.0825783972125
2006 24.2871232876712
2005 24.1934246575342
2004 23.9562841530055
2003 24.4635616438356
2002 24.4090410958904
2001 24.3632876712329