Year	% of revenue
1990	6.368017556063942
1991	6.917067715437472
1992	3.8687745239406093
1993	3.380981760355929
1994	3.8186879059245435
1995	3.2669847749184022
1996	2.4615239798559796
1997	1.8607888679013405
1998	1.967284938633031
1999	1.8604759596975762
2000	1.2822969091147556
2001	0.9193960406326325
2002	0.9343204803725117
2003	0.8548308661010816
2004	1.271701854664966
2005	1.3017376827155225
2006	1.3772012713684392
2007	1.2123562489745388
2008	1.106682125800109
2009	1.7789037687289795
2010	1.5612300337589957
2011	1.5206494604011578
2012	1.9380826580378798
2013	0.9001917901020501
2014	0.6774354145773878
2015	0.641734263836559
2016	0.6497126901729001
2017	0.8513637580153111
2018	0.7468268882765355
2019	0.6976344334346108
2020	0.5895469804206728
2021	0.6351585647803837
2022	0.6511471515350462
