Year	% of revenue
1972	0.6932409012131715
1973	0.8888888888888888
1974	0.7797270955165692
1975	0.8376288659793815
1976	0.864304235090752
1977	0.9189925119128658
1978	1.0039177277179236
1979	1.097470238095238
1980	1.0834075393291778
1981	1.0194516053433327
1982	1.1139240506329113
1983	1.1473112629181994
1984	1.2628886579809766
1985	1.5067695443295968
1986	1.577507792125183
1987	1.696380334954079
1988	3.8256937671779414
1989	4.364363579327112
1990	4.81935401506447
1991	5.196394792478023
1992	5.819920690459529
1993	8.506411414123171
1994	7.822519882796149
1995	7.812367700601168
1996	9.10077014860614
1997	9.521710381309235
1998	11.161988761297629
1999	11.478687647964612
2000	13.310236535930752
2001	14.874805067498203
2002	15.117199005064515
2003	14.724645466166583
2004	15.817800343431646
2005	16.171697156519766
2006	16.167712032266422
2007	14.03804033220375
2008	15.828052642657234
2009	16.384512586111555
2010	16.10871313952236
2011	16.0731519068186
2012	23.47819313428418
2013	24.39291229822782
2014	25.78534759533869
2015	26.30894747320298
2016	25.96819619319649
2017	25.79281702431092
2018	25.51348113747852
2019	26.975684000999422
2020	28.7031530236454
2021	26.828265722121742
2022	26.230177239357566