2017 23.9808219178082
2016 24.1508196721311
2015 24.1523287671233
2014 23.9638356164384
2013 23.852602739726
2012 24.0049180327869
2011 23.726301369863
2010 24.0131506849315
2009 23.778904109589
2008 23.4560109289617
2007 23.713698630137
2006 23.7432876712329
2005 23.6832876712329
2004 23.3139344262295
2003 23.5043835616438
2002 23.587397260274
2001 23.5602739726027