2017 11.7942465753425
2016 10.9379781420765
2015 8.86356164383562
2014 9.85424657534247
2013 12.5547945205479
2012 10.8371584699454
2011 12.943137254902
2010 12.0355311355311
2009 10.0635616438356
2008 13.0322404371585
2007 9.77912087912088
2006 11.1961643835616
2005 6.87616438356164
2004 15.5534328358209
2003 NA
2002 NA
2001 NA