Year	% of revenue
2009	4.461086693355827
2010	4.131280631460645
2011	3.276927111015551
2012	3.3147940416812647
2013	4.2225938093114825
2014	4.042656325739215
2015	5.685372304579954
2016	7.218984624164662
2017	7.528570116439309
2018	9.007485428885067
2019	7.98549286756141
2020	9.005962995173794
2021	9.369280103024654