Year	% of revenue
1995	5.961152042866711
1996	6.813385589388002
1997	10.787229690928186
1998	11.428571428571429
1999	12.353765341364817
2000	11.638130686721198
2001	10.601422531975542
2002	10.0547821758774
2003	9.312166505690758
2004	8.245035585859556
2005	6.059916754312237
2006	5.218264299823058
2007	4.191168459174837
2008	4.001612727508087
2009	6.026097626672254
2010	5.710668330171198
2011	5.7881206049167115
2012	5.796217046099054
2013	5.956251153134631
2014	5.645226361142095
2015	5.88889439522665
2016	7.317823274143413
2017	6.372483338518189
2018	5.962850142340589
2019	5.432276405821463
2020	5.259185616307
2021	4.732890206996799
2022	3.9771210235249255