Year	% of revenue
1990	19.139066526677485
1991	19.87519500780031
1992	18.713824407481873
1993	17.799292762219814
1994	18.092288032003555
1995	16.59962155722195
1997	17.291461741168472
1998	17.734227817855995
1999	17.430515437447845
2002	13.276885856051074
2003	11.94241367664058
2004	11.430278076073837
2005	9.962857797652696
2006	8.737159203710998
2007	8.087486235578528
2008	6.5515223577172845
2009	6.893809143033747
2010	6.46711381229485
2011	6.120994827762131
2012	3.9349099281996986
2013	3.236512960138591
2014	3.137007523042771
2015	3.1116459231605975
2016	3.58060515132164
2017	3.227323309525327
2018	3.49812574892911
2019	3.438840220051583
2020	3.192713506911916
2021	3.979089859534212
2022	4.039569378466077