Year	% of revenue
1990	32.63813651137595
1991	23.15912379115161
1992	19.241060345540976
1993	25.416892486693587
1994	23.01942374802438
1995	25.687445847963886
1996	26.17492379325361
1997	27.226873802078078
1998	31.464718071763553
1999	32.71812567896501
2000	32.26531108512141
2001	32.46148066713441
2002	33.16508239071004
2003	36.140975602430245
2004	33.91397360574718
2005	37.42238074885935
2006	36.11535324396437
2007	34.60388457205913
2008	34.617694988281585
2009	33.464136420505106
2010	36.290175726122186
2011	39.39272426528385
2012	40.014842906309795
2013	39.52893721106523
2014	37.6134123775382
2015	38.29881592338237
2016	36.03111405738441
2017	33.82787229059621
2018	33.08092181844246
2019	33.706206396740185
2020	32.53449405755195
2021	33.51980618150412
2022	32.43314991794575