Year	% of revenue
1990	0.9325532076043324
1991	0.8429423459244533
1992	0.5942217061676115
1993	0.47524314765694076
1994	0.3251189746972624
1995	0.25514920681877007
1996	0.3341182460383122
1997	0.7624500439329951
1998	1.185620275194431
1999	1.3367477592829706
2000	1.2495925241768988
2001	1.1436889166146809
2002	1.5270926994412186
2003	1.9265463818425386
2004	1.9576719576719577
2005	2.032472997785491
2006	2.1059807860033546
2007	1.9649097398028534
2008	2.031499430583391
2009	1.9247784812223272
2010	0.49191239284348554
2011	0.5235828484951162
2012	1.0202413484643853
2013	1.0545047685817548
2014	1.1085902761745352
2015	1.2241484397518092
2016	1.143084482779961
2017	4.1888124071007855
2018	1.3027425038281524
2019	0.9443506869132466
2020	0.8456121399608817
2021	0.7642444194528408