Year	% of revenue
1990	3.0949508874719975
1991	2.4158236448739245
1992	3.061818365849338
2014	0.06902540018890212
2015	0.04626443166541373
2016	0.0455514567013941
2017	1.108804719137084
2020	0.03086667824023852