Year	% of revenue
1990	14.604810996563575
1991	18.089315997738836
1992	14.316918189038919
1993	18.633093525179856
1994	20.133600534402138
1995	14.607817532863237
2003	7.176188733109057
2004	6.2146700327274695
2005	9.233873360631417
2006	9.244591559285968
2007	8.96637352010026
2008	17.031981029289238
2009	25.122122261527352
2010	19.027349534012547
2011	20.076453639372602
2012	19.77082684363993
2013	19.525487931904824
2014	17.967043580682464
2015	19.225195445970154
2016	17.986011294310305
2017	18.225701318569364
2018	18.12589207794193
2019	19.073819504055937
2020	20.12615019818645
2021	22.481473186674354
2022	25.13523564800446