Year	% of revenue
1999	61.21330681494217
2000	45.62557071081203
2001	29.751820148288783
2002	41.62512258680066
2003	41.938093348392805
2004	34.7436421544881
2005	29.949305008512695
2006	45.99552360368298
2007	50.069710236304374
2008	36.58874745992323
2009	16.18501208702659
2010	49.75901155779827
2011	61.97014058399055
2012	56.675111887890814
2013	57.710993995402625
2014	54.187430649730395
2015	35.651236524511
2016	31.991406247803837
2017	38.62004579037027
2018	52.69482916756395
2019	49.034347538689566