VBA not overwriting cells

HI I have this code and it is averaging every 12 cells.

 Sub avg_sun()
Dim i As Long

For i = 35 To 8674 Step 12

Range("CC" & Rows.Count).End(xlUp).Offset(1).Value = WorksheetFunction.Average(Worksheets("sun").Range("BP" & i).Resize(12))

Next i

End Sub

However I have noticed a problem. When the code is run the first time and the destination cells were the averages are printed to are blank the code works correctly.

However if the code is run for a second time instead of overwriting the answers already in the cells the new answers are placed at the end

For instance if the first time run the code puts the averages in cells C2 to C722 the next time the code is run instead of overwriting C2 to C722 It places the averages in cells C723 to 1443.

Any idea how I can change this code to over right the cells.

Cheers

David