2017 26.8249315068493
2016 27.2581967213115
2015 26.3739726027397
2014 26.1301369863014
2013 26.0879452054795
2012 26.2833333333333
2011 26.3101369863014
2010 27.5030136986301
2009 26.2545205479452
2008 25.7948087431694
2007 26.4355223880597
2006 26.326301369863
2005 26.7147945205479
2004 25.8595628415301
2003 26.601095890411
2002 26.0216438356164
2001 26.4183561643836