Year	% of revenue
1990	29.04759727493027
1991	37.866142364176234
1992	21.037447911585577
1993	12.649176645205287
1994	14.44752432727876
1995	12.871315003220026
1996	13.330263285065353
1997	32.46043835216433
1998	22.39268056564818
1999	20.073034066627372
2000	19.32404234275752
2001	18.563637355293597
2002	17.841230160484567
2003	16.970188420081627
2004	14.757870861434174
2005	14.326511697494137
2006	15.978654910860811
2007	17.187678133839096
2008	15.465207490252828
2009	15.136582418446926
2010	15.159735559381604
2011	15.344099579160067
2012	14.59382042187532
2013	14.879416337656748
2014	15.183617155258386
2015	15.624588948619818
2016	16.695251238884413
2017	17.126672573864997
2018	16.08343022375897
2019	15.72799447473901
2020	16.867605226037956
2021	18.29904265057497
2022	16.474351871855884