I cant figure this out have been working on it for hours. Confused on part b.

1. Because of water shortages during a drought in a Canadian city, watering of lawns and gardens was permitted only from 06:00 to 09:00 and from 19:00 to 22:00. The peak consumption, as a percentage of total system capacity, was recorded each watering period for a week in July. Assume that the water consumption was normally distributed.And there is only 7 days but 14 watering periods so two watering periods a day.

88, 95, 65, 94, 67, 94, 75,

93, 77, 100, 85, 100, 85, 100

a. Find the mean and the standard deviation.

µ = 87, σ = 11

b .Water pressure problems occur in the system after 99% capacity is reached. On what percentage of the days were there problems?