Year	% of revenue
1990	64.6598434677905
1991	62.217240676584474
1992	58.05425631431245
1993	59.736594543744125
1994	59.88839652059741
1995	56.913524155686815
1996	57.40119585824704
1997	58.58080641617227
1998	57.26851151440204
1999	56.697952709500235
2000	56.10562112593247
2001	57.45513866231647
2002	57.08498192928537
2003	58.70602596826101
2004	51.2075115700668
2005	54.95756118711004
2006	58.57706373942876
2007	44.771494733249604
2008	43.31185938624267
2009	50.50058033896657
2010	36.87655217298244
2011	36.54498574339503
2012	34.78359304071458
2013	39.95272360534402
2014	35.233362466792684
2015	28.260484010090263
2016	20.689507933401757
2017	20.829143564686103
2018	21.153405485440317
2019	18.337425343314624
2020	19.438668239790186
2021	15.673285054910387
2022	19.636878578573004