Year	% of revenue
1990	20.62793185746029
1991	15.985868619118323
1992	16.95571925494329
1993	15.230250894077685
2001	22.307181909115133
2002	27.075510267533232
2003	21.74854016779827
2004	19.470399781510224
2005	20.76830912328738
2006	20.125870581304593
2007	18.735421221066414
2008	20.139145051452505
2009	22.613223293105854
2010	24.777141171741803
2011	24.683424988654323
2012	35.20475521054776
2013	34.159547930667756
2014	36.31222035831359
2015	29.659688484343054
2016	28.25334785769834
2017	33.75299568705161
2018	39.415864972390494
2019	42.49394836056545
2020	43.034694150211166
2021	39.90414709504084
2022	39.755782408213086