Year	% of revenue
2012	3.0236311954664057
2013	2.5710690863255663
2014	5.173364613514442
2015	5.167349078458411
2016	8.258475984050111
2017	7.458714438213641
2018	5.710326383635309
2019	4.246847420845916
2020	4.934128539001211
2021	5.079876536443178