Year	% of revenue
1999	0.24129589194404832
2000	0.3607124142675762
2001	2.554731509725484
2002	2.7771886862756165
2003	1.7640290268831973
2004	3.2571958186996075
2005	2.295776233578126
2006	0.549478665151843
2007	1.0416458871848608
2008	4.77954250395123
2009	8.444077356970185
2010	4.297757082166114
2011	1.739550975567045
2012	2.321397119592462
2013	2.1035186289184296
2014	3.3265371926824354
2015	9.485748177466183
2016	13.702091196250151
2017	16.540270557942133
2018	19.57638534168721
2019	24.780659695909712