Year	% of revenue
1990	17.758821248545946
1991	9.002690950642645
1992	13.430901712189335
1993	13.341651919363487
1994	14.110623228831617
1995	14.922629225149192
1996	16.391777370179867
1997	16.471641251775758
1998	18.900302495588605
1999	19.957720891824938
2000	17.905001032478296
2001	17.97745524680103
2002	19.667053100982034
2003	20.713908985730253
2004	19.970254772743083
2005	19.829888118407418
2006	19.867308018399154
2007	22.408371836233183
2008	23.066328115234384
2009	24.244860511212593
2010	22.934621145859023
2011	24.288701054902077
2012	23.031282986438896
2013	24.73002484758519
2014	25.09340826633902
2015	24.16492556187151
2016	25.258799392409237
2017	27.050863696461295
2018	26.566032532633894
2019	27.151926375640013
2020	27.44303689582696
2021	26.87364949837881
2022	25.376091019659704