Year	% of revenue
2010	40.14847938201291
2012	29.775668640975095
2013	31.329546300413213
2014	28.79766503870457
2015	24.67545438061656
2016	21.048591737050977
2017	27.79370309598018
2018	22.173673135595124
2019	24.827308243591965
2020	22.502994877157334
2021	20.34278976841744