Year	% of revenue
2006	11.185519988613336
2007	8.463967311172027
2008	3.1614885424301673
2009	4.844041334837514
2010	4.5548587550304225
2011	3.830635513051106
2012	4.224652213221854
2013	3.703643184550086
2014	3.8065492380086408
2015	4.570932221595079
2016	6.381246586407016
2017	7.422589029193877