Year	% of revenue
1972	4.053708439897703
1973	4.003075345976423
1974	4.268163971798878
1975	4.295195845799379
1976	5.932110594032293
1977	4.692037677719129
1978	4.334766044739664
1979	2.280073381672053
1980	1.0341437592165417
1981	0.9280593958013341
1982	0.8556409450618598
1983	0.9063058463109532
1984	1.018180999955
1985	1.5577378936674622
1986	0.7159946675612965
1987	0.7877732105620014
1988	0.8296456144699512
1989	0.7216733559740757
1990	0.8100793621767892
1991	0.9105730101357337
1992	0.9867587723905282
1993	0.9495219169228692
1994	1.04236215033959
1995	1.2943571844095403
1996	1.4678288958031493
1997	0.9492678995208883
1998	0.764850147566197
1999	0.822485327267927
2000	0.9499649160684407
2001	0.9228563748768033
2002	0.9840268874952358
2003	0.8814448105152398
2004	0.978376227115946
2005	0.9796437659033079
2006	0.7614175005642917
2007	0.6465850470179778
2008	0.8840797841326662
2009	0.6664953828947965
2010	0.5744743855493041
2011	0.5359825670316581
2012	0.6705497192894803
2013	0.8283614575064655
2014	0.6328633268359365
2015	0.7849527908741463
2016	0.6268990116132441
2017	1.0757523757677605
2018	0.7929868790465823
2019	0.8381732523136491
2020	0.9341850788255289
2021	0.884699833984898
2022	0.9020554048236438