Year	% of revenue
1973	38.60242321780783
1974	41.269841269841265
1975	43.982827863176844
1976	36.53028441840688
1977	40.40231844527787
1978	44.769467628231105
1979	43.37799717912553
1980	51.56396535554697
1981	47.59286058851905
1982	47.13592869314458
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	46.37441899315075
1992	40.23081240353585
1993	41.146352441886634
1994	40.571722205797464
1995	33.965070268795195
1996	33.34785657392216
1997	30.37046326993544
1998	29.971279754660955
1999	26.293084474182333
2000	27.46752217997465
2001	24.829395914887627
2002	20.92135764821987
2003	19.55585137480999
2004	19.90958277058448
2005	19.595839765574897
2006	16.832841281798146
2007	13.62823089587791
2008	11.434361924686193
2009	2.1748862357169867
2010	2.1761481492895847
2011	2.085759010150079
2012	1.8468530893919084
2013	1.6383931624737922
2014	1.3634247309638412
2015	1.099989251237109
2016	1.351409559100048
2017	1.1227434988961655
2018	1.1960944312964665
2019	1.1823475966676518
2020	1.0712499746147313
2021	1.1185189716837063
2022	1.1038408632171626