Year	% of revenue
2002	5.662441795335788
2003	7.087293255524429
2004	6.323288046949678
2005	7.094770715355353
2006	9.7508361219318
2007	10.275170468273954
2008	10.546794493057268
2009	11.384454028231408
2010	10.300443142296347
2011	12.187610408029173
2012	12.158712077463987
2013	14.232094800890849
2014	15.221072042088512
2015	18.18367586127961
2016	18.32037651238866
2017	20.670267585943368
2018	18.486934735960954
2019	18.50131370293305
2020	24.96185162981162
2021	27.27178990446926