2017 7.19945205479452
2016 6.4551912568306
2015 4.52876712328767
2014 4.78082191780822
2013 7.28821917808219
2012 5.44836065573771
2011 6.91616438356164
2010 6.74191780821918
2009 4.74958904109589
2008 6.24207650273224
2007 5.42383561643836
2006 5.92767123287671
2005 6.41506849315068
2004 7.18032786885246
2003 4.35452054794521
2002 4.29424657534247
2001 5.32027397260274