Year	% of revenue
2005	10.735185919494487
2006	12.494516281934704
2007	12.367534618787495
2008	13.031224504932137
2009	10.553605992415063
2010	75.2375668156669
2011	10.637254901960784
2012	10.674693543174524
2013	10.960883469687165
2014	12.516931174321213
2015	16.15673443138071
2016	15.573330932292262
2017	15.621992872750845
2018	18.067359761439523
2019	15.195247719834121
2020	15.496254171859372
2021	14.486427664030632