Year	% of revenue
1985	2.5818639798488663
1986	1.8744906275468622
1987	1.0101010101010102
1988	1.377144237738584
1990	1.278251204149685
1991	1.3351807532434816
1992	1.462303727675896
1993	1.5151515151515151
1994	1.4356999037030553
1995	1.3665480427046264
1996	1.5212527964205815
1997	1.4998351829469287
1998	1.836004356620507
1999	1.8952865439157252
2000	1.9801562170149885
2001	2.0909816440542697
2002	1.8779515938606848
2003	1.5096065873741995
2004	1.427732079905993
2005	1.4351558574892418
2006	1.497207069962488
2007	2.242955923925306
2008	3.2478217474575812
2009	4.29477879354647
2010	3.1288475744890425
2011	2.825997411000038
2014	19.690285723776025
2015	18.579475748738453
2016	17.556016490428235
2017	16.525658933535052
2018	14.805229945504875
2019	15.274777109234087
2020	24.10119025963121
2021	12.666323567138019