Year	% of revenue
1972	1.4072372199885124
1973	1.3471502590673576
1974	1.2221999599278701
1975	0.906035364606167
1976	1.1831442463533226
1977	1.1917175629375838
1978	1.1336866902237928
1979	1.2570023227216833
1980	1.1946294534305952
1981	1.1380957219794736
1982	1.6247251404837528
1983	1.460002027780594
1984	1.5920792079207922
1985	1.4378019675184819
1986	0.9845173413946648
1987	1.1181379580127788
1988	1.4035160893412024
1989	4.111686703808686
1990	0.6524058319884017
1991	0.5396357915725353
1992	0.34853954354308847
1993	0.39125376890387215
1994	0.39149216348356847
1995	0.36986092006724747
1996	0.3776063633133164
1997	0.33886521211922144
1998	0.4196003129222673
1999	0.8282408547951416
2000	1.4449213945949304
2001	1.3714492022359663
2002	1.449171722878984
2003	0.6893669920210056
2004	0.6150981046623194
2005	1.3350251935407476
2006	2.4427558691367137
2007	0.45649358577874677
2008	0.4571839765653945
2009	0.5432117636808789
2010	0.5488566892190141
2011	0.5499526728253239
2012	0.4962193753998168
2013	0.6388442467124841
2014	1.4594427503498228
2015	3.370297452814255
2016	3.8414924302495392
2017	3.9253042496852304
2018	1.2418477539652062
2019	1.2541021041692275
2020	1.239885658700435
2021	1.575829745065262
2022	1.4678422470776373