Year	% of revenue
1990	48.820859540195826
1991	49.7933565338591
1992	46.617277491061586
1993	48.80491889601983
1994	48.807794971347505
1995	52.602316661493845
1996	29.171455690741222
1997	32.01698327639642
1998	30.807621090170016
1999	30.296185310940455
2000	32.082386551655674
2001	36.37087450073576
2002	39.63835590104649
2003	36.71924698613656
2004	36.290993061772134
2005	28.629981038427093
2006	27.533707856117516
2007	23.120682204803657
2008	20.501224021115362
2009	23.391251348725657
2010	20.860077239386797
2011	23.69384413859996
2012	23.418740494845245
2013	20.607963046026374
2014	22.559608583810814
2015	25.039177098355303
2016	15.907014199760825
2017	14.23217811554145