Reference can be zero. Please add an if statement for reference = 0 to cover the divide by zero cases.
For R = 0 To 6
If Results.Range("G36").Offset(R, i).Interior.Color = RGB(0, 155, 118) Then
If Reference = 0 Then
Results.Range("G36").Offset(R, i).Value = 0
Else
Results.Range("G36").Offset(R, i).Value = Results.Range("G36").Offset(R, i).Value / Reference
End If
End If
Next R
Reference can be zero. Please add an if statement for reference = 0 to cover the divide by zero cases.