Year	% of revenue
2008	14.367192362694649
2009	14.568188333441631
2010	15.061127359261747
2011	14.895144473541984
2012	12.599324814943547
2013	13.078273079402722
2014	15.28238351722547
2015	14.451572052860516
2016	14.381811860992558
2017	13.941165306905042
2018	14.586902616114411
2019	15.268394995966943
2020	15.874567877033101
2021	16.95321933863829
2022	16.12880465626811