Year	Percent
2002	20.08
2004	15.24
2005	14.45
2006	14.57
2009	16.84
2010	16.68
2011	16.57
2012	17.57
2013	13.41
2014	13.97
2015	15
2016	15.54
2017	14.81
2018	9.55