2017 28.3178082191781
2016 28.5773224043716
2015 28.38
2014 28.1068493150685
2013 27.9731506849315
2012 28.2920765027322
2011 28.4372602739726
2010 29.418904109589
2009 28.7021917808219
2008 28.2844262295082
2007 29.0695890410959
2006 29.218904109589
2005 29.4698630136986
2004 28.8901639344262
2003 28.9490410958904
2002 28.6580821917808
2001 28.7364383561644