Year	% of revenue
2006	76.19533408672609
2007	83.23912278076374
2008	92.91623141771677
2009	88.25339265352395
2010	88.7827910534293
2011	90.15175298940412
2012	88.01647194877853
2013	88.93533441176663
2014	87.50377723429484
2015	85.43192291139135
2016	81.026521681192
2017	78.82994719036073