Year	% of revenue
1983	47.489028108144325
1984	49.0546569148129
1985	46.44529587058322
1986	50.4413821566964
1987	48.724560785114
1988	49.06753277854278
1989	48.0209402320053
1990	45.74278985024219
1991	23.587123028784625
1992	21.27103503182983
1993	21.481172073590304
1994	21.1981158514597
1995	17.004844611463454
1996	16.675036606748282
1997	15.186713643385527
1998	14.985907128386119
1999	36.088712721507235
2000	27.46752217997465
2001	24.829395914887627
2002	20.92135764821987
2003	11.086088717078242
2004	10.414178586107042
2005	19.595839765574897
2006	16.832841281798146
2007	8.779550606730707
2008	7.559281311529883
2009	3.5262890059836467
2010	2.1761481492895847
2011	2.085759010150079
2012	1.8468530893919084
2013	0.9938424382490658
2014	1.3634247309638412
2015	1.099989251237109
2016	1.5055663291603036
2017	1.5553060244876915
2018	1.6175451844468773
2019	1.1823475966676518
2020	2.678203540522511
2021	1.073845938441465