Year	% of revenue
2002	15.942105578182886
2003	15.745803572976442
2004	10.275670757458485
2005	9.817777237175715
2006	8.38729519199146
2007	8.037416091014066
2008	7.487248773543829
2009	7.37524882049193
2010	6.411096303046523
2011	5.237465668084945
2012	5.6194640696535725
2013	7.285508451490471
2014	6.831250947146229
2015	7.731238811765105
2016	8.734903617499338
2017	8.853967564538635
2018	10.434172361894259
2019	10.62285782628436
2020	9.850611885238138
2021	8.890850630353127