Year	% of revenue
1990	17.758821248545946
1991	9.002690950642645
1992	13.430901712189335
1993	8.76408795991564
1994	7.146848602988953
1995	9.403505476573413
1996	10.73837907771925
1997	12.375475556923888
1998	12.350561784053014
1999	11.3780408992291
2000	12.542780973105764
2001	13.925403441273913
2002	15.9617973814044
2003	20.015400046678305
2004	21.747028580707173
2005	22.385405312374505
2006	22.541853336477246
2007	23.461748453205995
2008	25.892724582024467
2009	29.020402110801747
2010	27.461451179605806
2011	29.562277460439486
2012	29.960932672803693
2013	31.0931977963448
2014	32.80841904135156
2015	33.75932948616716
2016	34.52307976366322
2017	35.89781514108812
2018	40.37040229041441
2019	40.35375096957815
2020	39.20540644315302
2021	38.87148680949937
2022	41.62980949191276