Year	% of revenue
1990	50.26017468871957
1991	51.369262255140825
1992	47.37839001291434
1993	46.64316370324954
1994	43.405989263307674
2000	35.74419489912447
2001	32.562154696132595
2002	40.55145834933804
2003	41.189794501871546
2004	40.180616470848456
2005	40.99510370264458
2006	40.81102407748914
2007	23.97384768447338
2008	34.27349587535419
2009	27.866459560745437
2010	27.877887010139002
2011	14.53038408766956
2012	12.209385326948171
2013	11.264160455512197
2014	13.119646080487474
2015	15.200526388402475
2016	17.357458447296445
2017	17.274097827127406
2020	12.948826689284704