Year	% of revenue
1990	37.59396463875141
1991	29.56921166977033
1992	28.414690230602456
1993	26.847127112696096
1994	31.34091270111421
1995	20.863722187257043
1996	16.87570953755249
2006	25.12390013732981
2007	22.22606940346106
2008	26.557449757267076
2009	26.471465098013002
2010	29.404854858659075
2011	29.308775668078084
2012	24.012221645736922
2013	27.94648980302487
2014	28.440738262232546
2015	28.43869359929562
2016	29.276919969454497
2017	24.459513321232766
2018	28.225241145428853
2019	28.28501829958977
2020	27.20556149515852
2021	29.85069954737536
2022	34.04737115242029