2017 15.3484931506849
2016 12.7636612021858
2015 10.1164383561644
2014 11.6452054794521
2013 15.0643835616438
2012 11.983606557377
2011 15.8575342465753
2010 13.0890410958904
2009 11.8794520547945
2008 14.6551912568306
2007 11.3301369863014
2006 13.2164383561644
2005 13.4287671232877
2004 16.129781420765
2003 10.9493150684932
2002 11.5917808219178
2001 11.9424657534247