When Nestor filled his federal income taxes, he was happy to learn that he was due a refund of $664. He was less happy to learn that it would take 55 days for his refund check to arrive. His tax preparer offered to give him $597 on the spot, in exchange for Nestor's tax refund check when it arrives. What annual simple discount rate does this offer equate to? Round your answer to the nearest percent (whole number). 10