Year	% of revenue
1982	3.8183279742765275
1984	4.2085187539732996
1985	4.015316154403394
1986	5.152791468769603
1988	4.076071529946069
1989	4.735272184936615
1990	5.028958892498941
1991	4.21028280608409
1992	4.343466328900148
1993	5.379593359447864
1994	5.475867095107166
1995	7.3925485355179
1996	9.66147427612634
1997	10.719421325547954
1998	13.681757601887174
1999	10.609963121231633
2000	13.567961788346473
2001	13.840756749838834
2002	14.843391988236643
2003	18.141471568187796
2004	13.686015984030048
2005	14.65482665057344
2006	13.625266846940566
2007	13.113513206324978
2008	13.934157114833457
2009	15.912639712709028
2010	22.768298488557733
2011	25.214512497869705
2012	22.996705622739768
2013	25.521128322346705
2014	24.982219430917656
2015	27.31644022061096
2016	24.6762987446807
2017	24.324115687671714
2018	24.685488552540782
2019	28.85659854214584
2020	19.944620636632084