Year	% of revenue
1990	11.312398587381885
1991	10.270410816432657
1992	9.46201181989886
1993	15.014544002737695
1994	14.183520391154572
1995	14.264489452659612
1997	12.10973077343437
1998	11.601111979047007
1999	13.218649036095599
2002	17.820176704152814
2003	14.701780736162535
2004	17.140160824546374
2005	16.399367766517653
2006	18.02192031455443
2007	16.054955809843207
2008	15.237772442957384
2009	18.137882574126852
2010	14.898305635502036
2011	14.344208668364312
2012	14.749230107063916
2013	19.73607299838448
2014	21.405494392416056
2015	19.520755485717455
2016	17.772612907162646
2017	17.357283396539476
2018	16.322439594606074
2019	16.84398611806422
2020	25.838819092706327
2021	19.157074197591946
2022	18.114101011013208