Year	% of revenue
1990	18.983928456170798
1991	15.539245848940505
1992	20.06921322392051
1993	19.707505278982264
1994	20.96073586800524
1995	23.207709425143584
1996	17.6683767120064
1997	15.878876256197724
1998	14.143569246935847
1999	12.840286598780077
2000	11.61955803349852
2001	10.883945008847641
2002	10.92964284386783
2003	10.993645811006092
2004	10.381275404429323
2005	15.002994194533404
2006	9.640752512670733
2007	8.600152141163134
2008	7.490062993147767
2009	6.960821021402309
2010	6.95045455673897
2011	6.420417263218132
2012	5.564572628517202
2013	4.50003691997261
2014	4.14095812066104
2015	4.323602225119876
2016	4.294756244105814
2017	4.364288713411046
2018	4.405779161294973
2019	4.355930622308093
2020	3.8705635915451078
2021	4.339743233083408
2022	4.395385057268288