2017 22.2920353982301
2016 22.4704918032787
2015 22.5698630136986
2014 22.9650717703349
2013 22.178431372549
2012 22.2183098591549
2011 22.1670454545455
2010 22.4258389261745
2009 21.6954929577465
2008 22.4148514851485
2007 21.75
2006 22.2224852071006
2005 22.4245714285714
2004 22.2683615819209
2003 22.5125766871166
2002 22.4645833333333
2001 22.5377643504532