Year	% of revenue
1998	6.894205692255357
1999	8.642643655378949
2000	12.792207000442279
2001	13.70824223946055
2002	9.4744563820999
2003	12.424208899961013
2004	18.658634186943573
2005	24.186287118719317
2006	29.17573242928705
2007	22.52421778242879
2008	25.16616763288102
2009	25.53066095651576
2010	25.58368984173453
2011	25.613153560561653
2012	26.485029971633523
2013	25.40591338811908
2014	25.107388194177222
2015	13.226539517467021
2016	10.129163818444791
2017	9.164235590109856
2018	10.810827234348128
2019	8.371755847894415
2020	4.94036059620611
2021	7.892023635424918
2022	6.456754113930896