Year	% of revenue
2002	17.70636374475523
2003	15.449404759497915
2004	15.558591449144371
2005	15.995659378068366
2006	15.105240461940749
2007	14.942999283034485
2008	16.404312549808026
2009	13.82808194021861
2010	15.175882365638552
2011	19.194683421019963
2012	20.060095117957236
2013	19.2278878769171
2014	19.877850956112987
2015	18.348642518630086
2016	20.262318326834457
2017	20.45345169745072
2018	21.77372697672871
2019	23.535058220415124
2020	23.198370533793405
2021	25.31507671932748
2022	27.674344485014636