Year	% of revenue
1991	25.063697017268417
1992	27.404300719787734
1993	29.770656126678105
1994	32.08964476200603
1995	29.99176850575588
1996	30.50333350842346
1997	30.3567936195975
1998	32.9689993731768
1999	32.6228108070199
2000	33.735274044833616
2001	33.35663668413359
2002	33.555627118830294
2003	34.85996274375431
2004	35.63309246423832
2005	37.10565097398247
2006	36.11535324396437
2007	34.60388457205913
2008	33.454321489241615
2009	34.41383827762743
2010	36.290175726122186
2011	37.757749759176754
2012	36.790220334810435
2013	36.63425645703685
2014	36.949630427898384
2015	36.40801293055539
2016	36.44186734242072
2017	36.3963698860098
2018	36.77183338706417
2019	36.1730227186969
2020	35.18491952758072
2021	35.398876935909676
2022	35.50906364999318