Year	% of revenue
2003	5.86393007012807
2004	5.507153061429807
2007	5.19488735522846
2008	4.835614499333857
2009	4.491345438340108
2010	4.3816314611116525
2011	4.399771436881252
2012	4.361769670577791
2013	4.1249883008171295
2014	3.9646122419255523
2015	4.941556173317739
2016	4.448243046272038
2017	4.364288713411046
2018	3.737528696904821
2019	3.767240866697196
2020	3.9038825420762846
2021	3.9153509286213173