2017 8.55369863013699
2016 9.19426229508197
2015 6.56630136986301
2014 6.51452054794521
2013 9.41808219178082
2012 7.46092896174863
2011 10.9534246575342
2010 10.2309589041096
2009 8.59753424657534
2008 8.36420765027322
2007 7.18246575342466
2006 7.4172602739726
2005 10.5515068493151
2004 11.5281420765027
2003 7.45671232876712
2002 6.97506849315069
2001 6.99452054794521