Year	% of revenue
2002	30.30706882090321
2003	37.71361025824958
2004	30.66487306007413
2005	32.027617743208516
2006	35.045807160864356
2007	37.323380911717166
2008	29.500633398421527
2009	35.89551006527429
2010	35.72622267867428
2011	33.57732467750098
2012	30.207159702580093
2013	31.14703495349015
2014	28.79766503870457
2015	27.29112521202194
2016	23.764622474299895
2017	19.58982016935401
2018	20.599119955629515
2019	21.937256429805185
2020	29.277888697656724
2021	22.02570982032056
2022	19.406916757397287