Year	Percent
2002	15.3626
2003	13.9691
2004	13.8347
2005	12.6769
2006	11.9207
2007	10.2548
2008	9.3941
2009	9.9233
2010	11.1965
2011	12.8785
2012	14.8736
2013	15.5214
2014	16.6933
2015	15.6083
2016	12.9972
2017	11.0358