Year	% of revenue
2011	26.706986277417016
2012	28.490140481377086
2013	13.078273079402722
2014	10.879852502017663
2015	6.751065100507912
2016	7.4688098606751225
2017	8.553048201970157
2018	13.391775212108778
2019	15.442197110449035
2020	15.028111676233758