Year	% of revenue
2009	18.53437170680675
2010	18.53437170680675
2011	20.616914734835586
2012	24.27757270096235
2013	25.822437201856214
2014	31.942000253249287
2015	27.18696715702571
2016	32.503096912951236
2017	27.51654396904481
2018	26.323517446841592
2020	30.81669401036244
2021	28.36620568197962
2022	30.020037734540324