Year	% of revenue
1990	34.58342492855573
1991	31.70437050508751
1992	37.047951131269166
1993	35.99351495775422
1994	43.09519168291098
1995	45.01741319264853
1996	42.53315782125691
1997	42.860101409306324
1998	41.78904135571459
1999	41.9127201878902
2000	41.91710014557074
2001	40.741306743371716
2003	43.89238152888274
2004	42.70425739649481
2005	42.272333001120906
2006	39.17072221363614
2007	42.33402332310373
2008	38.360380440743484
2009	37.76874904757591
2010	40.18028569977187
2011	36.15125063701367
2012	37.13607476990048
2013	36.84163860354976
2014	38.7859609621327
2015	38.49644746648934
2016	35.38559324590086
2017	35.09532825057592
2018	36.18799958306307
2019	30.340080614512328
2020	35.60808004761914
2021	33.93439369183524
2022	28.1052882547554