Year	% of revenue
1983	24.034306006901403
1984	23.78683499742041
1985	23.664325244785015
1986	21.43856189668218
1987	17.08439233437842
1988	13.160809435430762
1989	11.427495096192567
1990	14.856907967826514
1991	7.792606617703429
1992	12.889364388943456
1993	9.503102594605021
1994	9.326209683096113
1995	6.212438103605443
1996	7.424340955519246
1997	6.678972068824481
1998	7.0832720387016055
1999	2.6173488546751784
2000	3.446241973643574
2001	4.432054994796926
2002	5.014436602691474
2003	6.32256369185286
2004	5.829569998257806
2005	6.010714765285184
2006	5.18711743815822
2007	3.2356277033319105
2008	2.6503475217263386
2009	3.954759291567457
2010	4.162491611586582
2011	4.202453735219709
2012	3.6457419494983974
2013	7.012499751896043
2014	7.3588197404749645
2015	5.290077629367557
2016	7.146683651642098
2017	5.351969483666691
2018	6.1976572904649325
2019	5.17572900680705
2020	6.60173575627006
2021	4.482614639875799
2022	1.9327473161666324