How do I sum up the 5 columns labeled:

From 65 to 69 years
From 70 to 74 years
From 75 to 79 years
From 80 to 84 years
From 85 to 89 years
90 years or over

into one cell in the empty column and keep on doing this as I move down the weeks? Basically summing up 5 cells into one and continuing to iterate down the empty column.
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