2017 24.0409722222222
2016 24.0419161676647
2015 23.9387186629526
2014 23.6972067039106
2013 23.7731428571429
2012 23.8144808743169
2011 23.8824657534247
2010 24.4356164383562
2009 23.6657534246575
2008 23.5185074626866
2007 23.5466911764706
2006 23.9603715170279
2005 NA
2004 23.2454545454545
2003 24.1428571428571
2002 NA
2001 23.2