An English professor assigns letter grades on a test according to the following scheme.
A: Top 14% of scores
B: Scores below the top 14% and above the bottom 57%
C: Scores below the top 43% and above the bottom 24%
D: Scores below the top 76% and above the bottom 8%
F: Bottom 8% of scores
Scores on the test are normally distributed with a mean of 69.6 and a standard deviation of 9. Find the numerical limits for a D grade. Round your answers to the nearest whole number, if necessary.