Year	% of revenue
1990	0.015509887553315237
1991	3.699293898040447
1992	11.702514217169174
1993	14.330763134210066
1994	18.809616634178035
1995	13.4029889294561
1996	10.420184657778226
1997	16.469296798833007
1998	15.932049429680974
1999	8.570604256104879
2000	11.095798565768208
2001	13.733034092123544
2002	12.759009187771376
2003	15.69028732145025
2004	10.120833159926905
2005	8.955309506052435
2006	7.94322329639236
2007	6.450543658085881
2008	5.352506304574263
2009	6.352403975964307
2010	6.546230033057348
2011	6.000424612633456
2012	5.637406336040727
2013	5.395133204345248
2014	4.903338663373029
2015	4.950012513334383
2016	5.333173048564752
2017	5.659003023450227
2018	6.27948957877232
2019	6.60887250028024
2020	6.612573694603566
2021	5.896761369164236
2022	5.423695783645922