Year	% of revenue
1990	2.853012610719785
1991	2.271093291695888
1992	3.3771731633648066
1993	2.524774623184217
1994	3.104175610848748
1995	3.140865740155338
1996	3.416343083958927
1997	2.853365798055489
1998	3.303677749583845
1999	0.6092906136772782
2000	0.5975755035407797
2001	0.7262980870296405
2002	0.608186853456044
2003	1.3709423610475588
2004	0.9642924729902361
2005	1.0004676946280378
2006	0.6922817910717076
2007	0.8917289778414756
2008	0.8403350176360045
2009	0.7441147480941034
2010	0.8483800541200691
2011	0.8067610059030388
2012	0.6074765671361435
2013	0.6365061970491102
2014	0.5559637867345946
2015	0.5491685049809566
2016	0.6483352800000929
2017	0.5757464223217523