Year	% of revenue
1990	14.328235331370129
1991	16.784426820475847
1992	18.47114425703508
1993	21.301446051167964
1994	27.348215248571123
1995	27.23132686886211
1996	24.947037383054592
1997	26.152714465633114
1998	25.051301082780302
1999	24.87303369629042
2001	25.85534665850964
2002	33.47038029970535
2003	31.26548733480176
2004	32.688075789787774
2005	33.857949486903145
2006	48.13248818378339
2007	48.85801440242668
2008	30.22867685943297
2009	24.81476051854489
2010	29.088918254103145
2011	29.659322590675487
2012	38.31179687127524
2013	33.19354741141211
2014	19.2231373676059
2015	18.801011062844943
2016	19.308737608618962
2017	18.74062025261004
2018	21.886260676947504
2019	15.185086304426362
2020	17.808866153635176
2021	17.120101771868384
2022	18.542059885559947