Please be clear and concise with the answer, thanks

Sandhill Inc. has been using the services of San Bernadino Brokerage Company (SBBC) for the past six months. SBBC has informed Sandhill Inc. that the geometric mean monthly return was 8.3 percent and that over the past six months Sandhill Inc. earned 17.3 percent, 20.3 percent, - 24.3 percent, 15.3 percent, -9.3 percent, and an unknown amount in the last month. Determine the missing return. (Round intermediate calculations to 6 decimal places, e.g. 1.251125 and the final answer to 4 decimal places, e.g. 14.5125%.) Missing return %