Year	% of revenue
1990	3.7167812674224123
1991	4.999512718058669
1992	5.0624192854068015
1993	5.847639484978541
1994	5.54297910872518
2000	1.4845831747240197
2001	1.5193370165745856
2002	0.8031164374791939
2003	0.8452938697602935
2004	0.7264239626776406
2005	0.880388558024465
2006	0.6577284548727338
2007	0.555364221805611
2008	1.1109061481882079
2009	1.4716709507741172
2010	1.6656337346132994
2011	1.2186570889097783
2012	1.5527759205604106
2013	1.5828532756620268
2014	1.7351655345833203
2015	2.1458817536374926
2016	1.9099048554129556
2017	1.8055422609361538
2020	1.300537178399774