Year	% of revenue
1990	11.920529801324504
1991	13.531689423272875
1992	10.233863423760523
1993	10.442144873000942
1994	10.585918266863615
1995	9.919733454490382
1996	10.266880560011666
1997	9.598577235772359
1998	10.352108507041512
1999	8.644870032851495
2000	7.970882271029205
2001	10.810222947253942
2002	9.959171901616
2003	8.567306625235823
2004	9.603340734364394
2005	10.950634839744488
2006	10.686079193801694
2007	9.729305345785328
2008	10.695887473157565
2009	14.682803736046038
2010	15.98662421655091
2011	9.76571980415655
2012	15.06614575136164
2013	10.8454762134972
2014	14.49430185817548
2015	13.184916240411962
2016	15.59004754653269
2017	11.075601301814931
2018	10.119607197975668
2019	9.379612269517898
2020	10.95712484386748
2021	15.538897880003857
2022	17.170250879138624