2017 6.89561643835616
2016 7.55546448087432
2015 5.60821917808219
2014 5.47945205479452
2013 7.53479452054794
2012 5.96420765027322
2011 9.16027397260274
2010 9.17205479452055
2009 6.54082191780822
2008 6.5431693989071
2007 5.44575342465753
2006 6.01534246575342
2005 8.53260273972603
2004 8.17267759562842
2003 4.95945205479452
2002 5.63150684931507
2001 4.69452054794521