Year	Percent
2004	36.7404
2005	36.4689
2006	35.2732
2007	34.5359
2008	33.5091
2009	31.7797
2010	31.8809
2011	31.7594
2012	31.4572
2013	28.98
2014	27.6452
2015	26.7227
2016	24.3557
2017	22.7382