Year	% of revenue
2012	52.27831124804984
2013	45.61043877457671
2014	40.49662309625947
2015	34.90321431147755
2016	32.23403672636476
2017	35.458944372076694
2018	37.45428358896819
2019	39.61118134170219
2020	27.163583506146953
2021	35.621548220828515