Year	% of revenue
1990	12.402167369054787
1991	14.856327695129407
1992	13.320860617399438
1993	14.506114769520225
1994	12.982110618742821
1995	12.29744055732243
1996	12.74609887705994
1997	12.906641397495056
1998	13.033605872641044
1999	11.004215212982212
2000	9.838224168526006
2001	10.951604132680805
2002	11.074509026344488
2003	11.874375762956387
2004	12.064104152306655
2005	10.974893348552229
2006	9.103936886118397
2007	9.517572549729888
2008	10.01772230574757
2009	11.714871261978987
2010	14.422218192276612
2011	13.891474603599189
2012	12.592646646603697
2013	14.821699675090747
2014	14.544256381753323
2015	13.944301064455663
2016	13.823003235843876
2017	12.93343067893535
2018	15.368016874662155
2019	13.538460016659295
2020	16.515461017224105
2021	22.1411229128413
2022	21.176021377526542