Answer: 1.3%
Explanation:
The percentage decrease can be found using the formula:
percentage decrease = [(original value - new value) / original value] x 100%
Substituting the given values:
percentage decrease = [(9.79 - 9.66) / 9.79] x 100%
percentage decrease = 1.33%
Rounding to the nearest tenth of a percent, the percentage decrease is 1.3%.