Year	% of revenue
2003	8.046342814994691
2004	8.186069313688145
2005	7.6540668811952495
2006	6.247527363840169
2007	6.630237580131741
2008	6.172587907825198
2009	5.971218389785456
2010	5.030773777097681
2011	5.2757269090617
2012	5.607603371022149
2013	5.054727801708369
2014	5.293866528642617
2015	5.351486780005802
2016	5.493256050547206
2017	5.7270077341460635
2018	5.377920330270483
2019	5.211760780940644
2020	4.954861619501419
2021	5.468909826840679