Year	% of revenue
1990	14.220664031399718
1991	7.878367670364502
1992	7.822481550412107
1993	7.616938103452138
1994	7.295867034273693
1995	5.22403936748977
1996	6.554411590674714
1997	7.56897491068223
1998	6.582822070971241
1999	5.56478572579346
2000	4.893369369101067
2001	4.284475563011045
2002	13.638532318527774
2003	16.470868921766662
2004	15.799544867660334
2005	15.823533104006767
2006	14.646726075415357
2007	15.728660258631969
2008	20.12405184144029
2009	13.68463878743203
2010	15.670198312605747
2011	15.326104507232952
2012	13.877942949219843
2013	10.717348850163258
2014	10.756430888943273
2015	8.045318056967668
2016	7.112525766352383
2017	6.409745579803458
2018	7.449360724693681
2019	13.164229084988865
2020	13.38199654506457
2021	15.042248351023593
2022	16.5697283450127