Find Maximum Range in a larger Range

Hi,

I am trying to find the highest 8 hour period of sales in a week long period. I have sales $ 24 hours/day for 7 days.

What is the best way to find the highest 8 hour period of sales?

Data follows this format (for 24 hours, 7 days)

Time 1/1/15 1/2/15 1/3/15
1:20 2 4 4 6 6
1:30 7 7 7 5 5
1:40 3 6 6 4 4
1:50 1 5 5 3 3
2:00 7 4 4 2 2
2:10 3 3 3 1 1
2:20 8 2 2 0 0
2:30 4 1 1 0 0
2:40 2 0 0 0 0
2:50 8 0 0 0 0
3:00 0 3 6 7 7