Year	% of revenue
1991	0.21616947686986573
1995	1.1511690165982509
1996	1.5442589035022907
1997	0.8121406129586817
1998	0.9941739269870116
1999	0.7408964321370396
2000	0.5163511187607573
2001	0.4226073593443183
2002	0.5059147384867198
2003	0.45572276318809224
2004	0.45126087597699455
2005	0.367085555049436
2006	0.2788263555250515
2007	0.2106002106002106
2008	0.24376750458144603
2009	0.22925895919880027
2010	0.2098391233387736
2011	0.22247127109713463
2012	0.3092688330871492
2013	0.31323529411764706
2014	0.39156543155214873
2015	0.33615844873908135
2016	0.2997864021884407
2017	0.22260925731553996
2018	0.1697774853832196
2019	0.14075620055331747
2020	0.25645056694244106
2021	0.230460318688784
2022	0.2354883164478367