2017 5.73123287671233
2016 6.51612021857923
2015 4.70520547945205
2014 4.76027397260274
2013 6.34109589041096
2012 5.72349726775956
2011 7.5158904109589
2010 6.32356164383562
2009 5.29232876712329
2008 6.03469945355191
2007 4.53150684931507
2006 5.75753424657534
2005 6.8972602739726
2004 7.00136612021858
2003 4.84027397260274
2002 4.56794520547945
2001 3.8972602739726