Sales taxes are not corporate taxes. Corporate tax rates specified by law are not the rates collected, according to the Oregon Center for Public Policy: 

"For over a decade now, Oregon consistently has come out at or near the bottom among all states in terms of its “total effective business tax rate.”… 

Corporate income tax contributions have shrunk due to corporations lobbying for and winning many tax loopholes and subsidies, pursuing aggressive tax sheltering strategies, and taking advantage of corporate structures largely exempt from corporate income taxes. In short, corporations have gamed the system…. 

According to a corporate-funded study, businesses in Oregon get a bigger benefit out of the taxes they pay in Oregon than just about any state in the country. On the other hand, the tax system directly subsidizes corporations through a long list of tax credits, deductions, and subtractions.”

http://www.ocpp.org/2017/04/14/blog20170413-8-key-things-oregon-corporate-taxes/