2017 22.5660273972603
2016 22.8303278688525
2015 22.9120547945205
2014 22.5890410958904
2013 22.6402739726027
2012 22.6724043715847
2011 22.561095890411
2010 23.0569863013699
2009 22.1531506849315
2008 22.2770491803279
2007 22.3816438356164
2006 22.126301369863
2005 21.9241095890411
2004 21.6027322404372
2003 22.6558904109589
2002 22.6446575342466
2001 22.8641095890411