Year	% of revenue
1984	8.215631081747032
1986	9.657763432323929
1987	10.088991294029995
1988	9.541569035841361
1989	8.768553379229669
1991	17.323928489949044
1992	17.22681602210611
1993	13.312488098703993
1994	15.276147799782414
1995	14.836323353820724
1996	16.216151310705083
1997	16.05773925048113
1998	18.517580075694294
1999	19.563187537367384
2000	17.366539348028663
2001	21.504672001163552
2002	20.655281736180555
2003	24.80476216481896
2004	21.214414073583658
2005	19.773064276964735
2006	14.641711089071292
2007	16.696911777498002
2008	16.9178043343859
2009	18.779698112980345
2010	21.645807920509384
2011	24.87759756435504
2012	17.867233130012515
2013	20.190747600613513
2014	20.974313760069755
2015	23.78229275478471
2016	26.51967880271319
2017	23.40725435656691
2018	25.4401047850416
2019	24.61895301005459
2020	19.97387335587998
2021	22.285250846478803
2022	23.28817096503188