Year	% of revenue
1990	12.937048760247924
1991	18.92489137181875
1992	21.875479053062655
1993	15.61924995731927
1994	16.161753693239838
1995	15.362259820073303
1996	12.262176690238132
2006	24.1582062782891
2007	27.458769353696916
2008	25.542825152224996
2009	26.510235799395044
2010	19.499274780125518
2011	21.95327915388979
2012	34.18595128446037
2013	26.946041706293467
2014	28.101078099666154
2015	32.58138229675666
2016	20.541572200382134
2017	31.716029395049468
2018	27.683848997935996
2019	25.766522856745226
2020	33.36072194044296
2021	20.696734470402255
2022	18.695474788865422