Year	% of revenue
2004	2.7248785909395297
2005	2.2164709333152066
2006	1.6680450079041171
2007	1.4255278675745502
2008	1.329753579363307
2009	2.2536082628847187
2010	3.7342493080084034
2011	3.852300392194431
2012	4.121250146439148
2013	4.294582102210289
2014	5.109236180395647
2015	6.185230354365815
2016	8.241988820486739
2017	9.607775630272277
2018	10.182016816812345
2019	9.964618863384512
2020	10.645255906756788
2021	10.944113113277924
2022	9.859041121420155