Year	Percent
2004	13.99641
2005	14.33566
2006	14.39599
2007	15.96253
2008	17.32176
2009	16.50586
2010	17.07005
2011	17.21942
2012	17.49164
2014	21.59917
2015	20.93122
2016	21.27738