Year	% of revenue
1973	1.8746674307232616
1974	1.673640167364013
1975	1.7003493037949948
1976	1.526687929914305
1977	1.640845466565434
1978	2.0663669079535127
1979	1.9432345992797315
1980	1.5961830308445029
1981	1.4035087719298238
1982	1.5276322506112243
1983	2.0686356570608617
1984	2.48474280732345
1985	2.6326078456926956
1986	1.9467470484802887
1987	1.938929525136426
1988	1.9881145326850358
1989	1.6033573657591713
1991	1.6762664303647912
1992	0.9867587723905282
1993	0.812788050203248
1994	0.7988085567289447
1995	2.356764916550497
1996	2.5395202633894227
1997	2.4091412864644206
1998	2.446939050127199
1999	2.471346629964708
2000	1.1858729418969938
2001	1.5644347315839875
2002	1.7539389782526587
2003	1.9187409475743231
2004	1.8446829322054912
2005	2.023697871946951
2006	1.9748789346246975
2007	1.828494499067545
2008	1.803942607372586
2009	1.8490866589963684
2010	1.6806440791680644
2011	2.173097026521955
2012	1.5220962354056837
2013	1.6688587038652858
2014	1.7324414568180309
2015	1.80278482850226
2016	1.6621670014542247
2017	1.62538946176411
2018	1.644292652046739
2019	1.6544357679088708
2020	1.6442892330828593
2021	1.6659310814454225
2022	1.4096731001207283