Year	% of revenue
1973	1.5779092702169626
1974	2.5440313111545985
1975	0.8863038360337904
1976	0.8409713691769819
1977	1.1421752471871804
1978	0.8589255327769224
1979	0.9943582510578278
1980	0.8716279582942571
1981	1.1384466956102268
1982	0.8039498405208196
1983	0.7671948809005327
1984	0.5432308579405785
1985	0.6226053639846743
1986	0.5594662142021875
1987	0.6344730348960169
1988	0.6825121235706161
1989	0.6650991803172212
1990	0.9309869795138426
1991	0.9246975816357614
1992	0.7489125859407886
1993	0.7627881554833938
1994	0.7102532696991454
1995	0.7709100832310001
1996	0.832590151881327
1997	0.6805095096841738
1998	0.6766295088351263
1999	0.6558964652022714
2000	0.6535171102661598
2001	0.6878913139545343
2002	0.6244386619475812
2003	0.549264399451935
2004	0.5289165298546693
2005	0.5533628899586055
2006	0.5490546528112441
2007	0.7143830711548904
2008	0.72017452103061
2009	1.3941466990610554
2010	1.9838446824909677
2011	2.166767147056504
2012	1.8019664282113892
2013	1.854424274727426
2014	2.872030475905345
2015	2.19354460308019
2016	2.4793333618752427
2017	2.195776004296699
2018	1.8683457852405025
2019	2.2395029772076485
2020	2.0962594348273966
2021	2.9768718903158304
2022	2.658882005994465