Year	% of revenue
2002	42.120514785337626
2003	34.170552882763495
2004	30.32051564825148
2005	35.14551753510231
2006	28.16523947382978
2007	27.303155093725177
2008	28.548105760810632
2009	36.40855220745736
2010	39.43465036031743
2011	32.84900432272085
2012	39.65661199890178
2013	32.48231082982043
2014	23.587818698622584
2015	21.242790190616024
2016	25.268642559678444
2017	22.815816186324543
2018	22.692249378725627
2019	20.395170914549222
2020	18.200893090010243
2021	16.931345952458376