Year	% of revenue
1990	30.72317790855591
1991	25.599228112939265
1992	26.053413941437327
1993	27.34532018181256
1994	27.01455692482514
1995	25.690990599631785
1996	27.162546413069528
1997	28.84595006649871
1998	27.933280960420838
1999	29.2961066286613
2000	27.60255621374823
2001	26.090212831332348
2002	25.96555503474137
2003	25.17802882742501
2004	24.383260222576414
2005	23.212358999509565
2006	25.078887638168702
2007	23.849747061300043
2008	21.412815390269213
2009	24.994501781244796
2010	24.362581842595652
2011	22.668902766437906
2012	23.907892099778756
2013	25.728108025136294
2014	25.295078038012292
2015	25.770109270528224
2016	26.034887459660634
2017	26.956224181440692
2018	27.27645071114685
2019	27.431174266972757
2020	27.158553521064665
2021	28.341825438944486
2022	25.8630210739197