Year	% of revenue
2011	26.895032270677525
2012	26.430456468055567
2013	32.78707623172542
2014	34.32863132706339
2015	35.128015113353584
2016	32.96359493691682
2017	38.5566454922251
2018	44.81204652827724
2019	44.709207030343855
2020	40.75624120996011
