Year	% of revenue
1990	2.454730647351743
1991	2.4560042841578493
1992	3.0904848112408443
1993	2.740716118858415
1994	6.350450291595646
1995	4.270503648146671
1996	4.134746744600274
1997	4.199690753976407
1998	6.199679686109748
1999	4.659733217518168
2000	3.7129911288658106
2001	3.6260411556544065
2002	5.7931578802249915
2003	5.714063108687183
2004	4.368308955244933
2005	6.136586562040216
2006	4.112203953506015
2007	4.463826281376285
2008	4.740819564918959
2009	4.0246070888289545
2010	4.213719174243496
2011	4.177975888371545
2012	4.172075519151595
2013	4.178876944330472
2014	4.326849702024284
2015	4.033653270665028
2016	4.151117661150242
2017	4.077577932460489
2018	5.791409870028061
2019	5.496921404458859
2020	5.102537014725579
2021	6.32495543357825
2022	5.761261946369762