Year	% of revenue
2005	15.23912818923665
2006	15.278087805923374
2007	16.315397321189884
2008	16.81971544049098
2009	17.544911679865198
2010	17.145967179111846
2011	17.554667580376552
2012	19.37866688350229
2013	20.93721674084789
2014	23.523590644300683
2015	22.491466668149705
2016	19.19164119754788
2017	22.021256161070276
2018	20.5352432359584
2019	17.570322153398042
2020	22.698868602996136
2021	23.185764718938774
2022	23.71155256830574