Year	% of revenue
1990	16.411902200126146
1991	12.470113275584996
1992	15.008117576689738
1993	16.224687718209328
1994	17.121133425669438
1995	13.32074886951132
1996	14.067523025378783
2004	10.811881760614819
2005	11.267617147902293
2006	9.295347933425123
2007	12.894662217326097
2008	10.934922925659434
2009	13.424092274083288
2010	11.447761670416744
2011	10.733692820829503
2012	9.677706845857227
2013	8.885866513161659
2014	13.297857438396973
2015	13.689451642925544
2016	10.061142198675222
2017	10.370632116697966
2018	10.489877702142493
2019	10.331162951219437
2020	17.631354559805754
2021	32.90912752250184