Year	% of revenue
2008	6.623986963163499
2009	5.157558948899153
2010	4.750001585346605
2011	4.556277485331746
2012	3.685594374071879
2013	4.0309266659750325
2014	3.3284499643172136
2015	3.896658307172097
2016	3.944744902737792
2017	3.4324263428594204
2018	2.9603774439471127
2019	3.248545774446352
2020	4.496501431113644