Year	% of revenue
1990	17.146047462734757
1991	18.6827526483742
1992	18.33492822966507
1993	17.4254095896588
1994	15.35060653451118
1995	17.784405154660476
1996	14.643729218620116
1997	16.152067306574942
1998	17.544533801773117
1999	16.31681272698563
2000	14.038144267961867
2001	13.00977516698722
2002	15.948434070667197
2003	17.427238438370818
2004	10.95182895012295
2005	17.11540187287628
2006	14.212015277536654
2007	12.989610328496473
2008	13.703074083623582
2009	13.157727897944502
2010	11.786491808459337
2011	13.125251995700676
2012	13.691384644229867
2013	11.468382308312595
2014	10.255536750071235
2015	6.154151806086262
2016	12.486545814966012
2017	7.960766231721991
2018	10.08698257002713
2019	7.104376028736651
2020	9.05470586350622
2021	8.961041002743292
2022	11.131979753441959