Year	% of revenue
1990	35.246219464908876
1991	34.264811509027396
1992	37.047951131269166
1993	35.99351495775422
1994	43.09519168291098
1995	45.01741319264853
1996	42.53315782125691
1997	42.860101409306324
1998	41.78904135571459
1999	42.641564263025906
2000	41.91710014557074
2001	42.28331068657496
2002	43.604266725551895
2003	44.525510204081634
2004	43.80033352168422
2005	41.77184313738016
2006	38.160996002876004
2007	40.34365321405176
2008	39.07812296592596
2009	38.56431401949234
2010	40.03975561289839
2011	36.349386041221024
2012	36.61142120013656
2013	35.86528215723531
2014	36.04931669094695
2015	37.05727125275827
2016	35.38559324590086
2017	33.45873152236196
2018	33.348220108620765
2019	30.340080614512328
2020	34.554626180891084
2021	34.79580984298643
2022	29.185881433304456