Year	Percent
2006	21.1678
2007	20.4278
2008	21.5237
2009	22.7753
2010	25.8448
2011	24.2449
2012	21.415
2013	22.7317
2014	18.9839
2015	17.2354
2016	14.2962
2017	12.4422