A psychology professor assigns letter grades on a test according to the following scheme. A: Top 10% scores, B: Scores below 10% and above the bottom 63%, C: Scores below the top 37% and above the bottom 20%, D: Scores below the top 80% and above the bottom 7%, F: Bottom 7 % of scores Scores on the test are normally distributed with a mean of 71.5 and a standard deviation of 9.5. Find the numerical limits for a D grade. Round your answers to the nearest whole number if necessary.