Year	% of revenue
1990	13.429991714995856
1991	17.044056116170317
1992	11.702514217169174
1993	12.058728273777394
1994	13.419373071759969
1995	13.4029889294561
1996	13.040354347348313
1997	14.390266559878684
1998	15.694836886719754
1999	13.039471511147813
2000	13.500855182898794
2001	12.787051917994638
2002	12.569236148169956
2003	12.410013455931823
2004	11.807166260536228
2005	10.280795171571013
2006	8.920442664943588
2007	8.36801281804423
2008	9.687932880147534
2009	12.300524793830995
2010	12.089697814168963
2011	10.618776529902686
2012	9.808468730243597
2013	10.5460469498312
2014	9.675576516669036
2015	9.68580836528995
2016	11.273367769579643
2017	11.198264347740434
2018	12.79505881589059
2019	13.693050803984322
2020	11.975351000486022
2021	11.92653841102938
2022	13.96944419056602