Year	% of revenue
2010	29.913354736171456
2012	34.281449961959495
2013	32.562679777001
2014	36.29177143237658
2015	36.25416527274747
2016	38.632605541119695
2017	35.87900368030804
2018	37.82391621394324
2019	37.305525747548934
2020	37.083761554889975
2021	39.029344474587845
