Jones, Inc. has $22,000 to invest in securities. Dow Company bonds yield 11 percent. Proctor Company preferred stock has a dividend yield of 9 percent. Municipal bonds issued by the City of Seattle yield 9 percent. The corporate tax rate for Jones, Inc. is 40% with 70% of the preferred stock dividens tax exempt. The investments are considered equally risky so the corporate controller of Jones, Inc. will decide which security should be selected strictly on the basis of after-tax rate of return. What is the after-tax rate of return on the highest yielding security?