Year	% of revenue
1996	27.034440719292895
1997	26.653042688465035
1998	22.37826232335498
1999	24.58261477353308
2000	24.800693519127964
2001	22.42188655421033
2002	21.59877385827526
2003	18.140981340704908
2004	17.981247107587677
2005	20.300461887246833
2006	16.2030038335257
2007	15.030600190694232
2008	15.861406883230009
2009	15.67241383954503
2010	16.742684803111793
2011	15.390008575172986
2012	14.648505136788643
2013	14.516975660143732
2014	14.91205570345579
2015	22.77567563866739
2016	28.969781707081694
2017	28.656551311012883
2018	19.46408400046512
2019	18.22790863936134
2020	19.682469301829595
2021	19.347240006522625
2022	19.538599205451362