Year	% of revenue
2012	3.326972594806942
2013	5.846910316568004
2014	4.805139273127769
2015	10.089232125969644
2016	13.364827078540822
2017	14.309921304568856
2018	14.313074506411514
2019	11.72073030958939
2020	19.25874070178655
2021	18.929572209747068