Year	% of revenue
1992	27.405032067094176
1993	28.387096774193544
1994	32.12835093419978
2002	32.211223702701844
2003	32.34827694023871
2004	32.28131561854446
2005	32.07945472716262
2006	32.18452042546278
2007	33.07263025966432
2008	33.454321489241615
2009	34.54586101290313
2010	35.29141050709054
2011	35.332313316042416
2012	35.62859871429785
2013	36.63425645703685
2014	36.741949274535756
2015	35.57364012769051
2016	36.550888417582804
2017	35.80967497642597
2018	35.02047480707069
2019	35.45761172987186
2020	32.902424796888596
2021	33.02827921754489
2022	33.15108432824746