Year	Percent
2002	38.8807
2003	38.5011
2004	37.2799
2005	35.1306
2006	31.1437
2007	29.2652
2008	28.2903
2009	27.4556
2010	33.5813
2011	36.0894
2012	41.9708
2013	50.162
2014	46.3663
2015	43.669
2016	31.3284
2017	27.742