Year	% of revenue
1997	1.2434241989478718
1998	1.145071842702294
1999	1.0494168971052784
2006	1.3772012713684392
2007	0.7143830711548904
2008	0.978551412316941
2009	1.2239902080783354
2010	1.195371957943482
2011	1.269417840163651
2012	1.1822875622131417
2013	0.9321548809752553
2014	0.6491822047594035
2015	0.633732849060177
2016	0.9502373826368699
2017	0.9407939708418722
2018	0.7496868078813137
2019	0.7244977349099757
2020	0.7949210865559466
2021	0.805041025131013
2022	0.8221930397610685