Year	% of revenue
2015	3.284041990186757
2016	3.5733797659838937
2017	3.0030525411728815
2018	3.0115224397972127
2019	2.5550696513245583
2020	1.600388772600163
2021	2.7546716260818096
2022	2.2574926038984344