2017 4.42794520547945
2016 4.27814207650273
2015 3.16602739726027
2014 3.16493150684932
2013 4.24767123287671
2012 3.67377049180328
2011 5.45260273972603
2010 4.61150684931507
2009 3.23287671232877
2008 3.91967213114754
2007 3.79698630136986
2006 3.74082191780822
2005 4.8586301369863
2004 5.19726775956284
2003 3.35452054794521
2002 3.29820895522388
2001 3.99565217391304