2017 6.41616438356164
2016 6.90273224043716
2015 5.03452054794521
2014 5.22
2013 7.46109589041096
2012 5.71338797814208
2011 8.61232876712329
2010 7.73123287671233
2009 6.23452054794521
2008 6.30081967213115
2007 5.09945205479452
2006 6.16986301369863
2005 8.00027397260274
2004 7.87049180327869
2003 5.14082191780822
2002 5.18931506849315
2001 4.92602739726027