A psychology professor assigns letter grades on a test according to the following scheme.

A: Top 10% of scores

B: Scores below the top 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.