Year	% of revenue
1985	3.023165595211705
1986	1.8226312167019296
1987	1.7605546613841772
1988	1.0409800043946384
1989	0.2666114461729609
1991	0.11168363073330456
1992	0.6781172706124663
1993	2.4733166879172446
1994	4.3656878714683405
1995	5.490446440786174
1996	6.813385589388002
1997	16.2470637402545
1998	13.393863380230487
1999	16.180135589675665
2000	12.31139776977501
2001	11.00528691309464
2002	7.78782406594601
2003	5.216250807217316
2004	4.663738060102576
2005	3.8916474413338316
2006	2.386695114814081
2007	1.98050529897239
2008	2.1129937505804928
2009	6.198555802567244
2010	5.710668330171198
2011	6.367520978057055
2012	7.022509772206496
2013	6.620934964547787
2014	5.4628356181557844
2015	4.68371217461819
2016	4.567914466334196
2017	4.2113944720416745
2018	3.602787649407837
2019	3.804436250110968
2020	4.597898867290469
2021	4.732890206996799
2022	4.631010861032336