Year	% of revenue
1990	19.25785827831475
1991	18.116556612346276
1992	20.36249558714978
1993	21.583704408450373
1994	24.828916960218987
1995	27.543134198219143
1996	29.91167538969525
1997	30.60582685575268
1998	30.414237573186576
1999	29.31340933170452
2000	33.62792778325801
2001	34.51828501447095
2002	32.11787774764157
2003	31.85473125875043
2004	37.01406415619157
2005	43.66514360313316
2006	46.33740656502325
2007	47.1308069998741
2008	38.008610501435086
2009	37.56303636202778
2010	44.51712527076587
2011	38.93126950996509
2012	47.039154779098986
2013	45.94012641522539
2014	40.501678683471845
2015	40.9031384724041
2016	40.79297272830146
2017	40.314065614394224
2018	39.26272962643324
2019	42.587983441445395
2020	50.276714706426326
2022	46.75229975319722