Year	% of revenue
1990	28.1783350748868
1991	28.767123287671232
1992	28.617265750336035
1993	20.303260933200633
1994	19.40256659117869
1995	19.418197589764244
1996	22.060081318999433
1997	20.150908908529587
1998	21.211360461054838
1999	21.441595500293595
2001	14.37585032460714
2002	19.390114715064254
2003	14.306855726872246
2004	9.402235400892668
2005	9.873014385455226
2006	15.139413036309676
2007	15.617501481209818
2008	10.325660020466856
2009	10.877086431129447
2010	13.835060161288526
2011	16.027201393358485
2012	20.02875330276648
2013	17.51778492611358
2014	20.140741225925876
2015	21.402276827975793
2016	20.357505757090117
2017	21.983561879360145
2018	21.63409532754102
2019	22.622330622266603
2020	21.278487490896016
2021	25.087131080924486
2022	27.17755611113173