2017 4.76794520547945
2016 5.01912568306011
2015 3.81013698630137
2014 3.48821917808219
2013 5.32191780821918
2012 4.23469945355191
2011 6.14356164383562
2010 5.16876712328767
2009 4.19780821917808
2008 4.5207650273224
2007 3.49369863013699
2006 4.23479452054795
2005 5.35890410958904
2004 6.53606557377049
2003 3.73178082191781
2002 3.39205479452055
2001 2.73698630136986