2017 4.34684931506849
2016 4.89808743169399
2015 3.34520547945205
2014 2.96739726027397
2013 5.30575342465753
2012 4.5379781420765
2011 4.97424657534247
2010 5.27178082191781
2009 3.76767123287671
2008 3.58497267759563
2007 4.15890410958904
2006 3.7227397260274
2005 5.22630136986301
2004 5.48989071038251
2003 3.62904109589041
2002 3.48767123287671
2001 3.86630136986301