7.6937%. If the credit rating is downgraded, the coupon rate will be increased by 0.25% for each notch till AA-. If the credit rating is upgraded above AA-, the coupon rate will be decreased by 0.25% for each notch until the initial rating is restored. If the credit rating is downgraded below AA-, the coupon rate will be increased by 0.75% for each notch till A+. If the credit rating is upgraded above A+, the coupon rate will be increased by 0.75% for each notch till AA-.