Suppose the spot price for robusta coffee is trading at 1,220 USD per metric tonne, the one-year effective annual interest is 1.0%, the present value of three-year's worth of storage costs is 30 USD per metric tonne and the three-year forward price is 1,215 USD per metric tonne. What is the implied annual convenience yield? Express your answer in percentage terms, then truncate your answer at two decimal points and include a minus sign if the answer is less than zero. For example, if your resulting calculations yield -0.026762 the answer should be input as: -2.67