2017 4.47945205479452
2016 5.22322404371585
2015 3.18684931506849
2014 3.38356164383562
2013 4.61205479452055
2012 4.59945355191257
2011 6.0772602739726
2010 4.92164383561644
2009 3.70876712328767
2008 3.57513661202186
2007 3.87561643835616
2006 3.43835616438356
2005 4.82602739726027
2004 4.64617486338798
2003 3.47671232876712
2002 4.10904109589041
2001 3.83561643835616