Year	% of revenue
1990	3.5006903913764895
1991	3.7600210011914137
1992	5.00657915850958
1993	4.955899899400301
1994	4.65271077804453
1995	4.660871403281634
1996	4.009015549929606
1997	4.404095545138683
1998	4.222073007724988
1999	4.329475518604934
2000	5.318758459314997
2001	5.514336395938249
2002	5.699860527114867
2003	5.118498246741986
2004	5.49339906163057
2005	6.7395561357702345
2006	6.942654778480192
2007	6.571824247765328
2008	0.9876751646125275
2009	2.8001415553392905
2015	1.8362932772243723
2016	1.623854249179586
2017	1.4504659807143243
2018	1.1465910491924547
2019	1.0523193582915287
2020	0.6643998349670646
2022	1.116221673771595