try
Sub Evaluate()
    Dim i As Long, iSrt As Long
    Dim clrSet&, clr1&, clr2&
    clr1 = 0
    clr2 = 20
    clrSet = clr1
    
    With Worksheets("2013")
        iSrt = 2
        For i = iSrt To .Cells(.Rows.Count, 1).End(xlUp).Row
            If .Cells(i, 5).Value <> .Cells(i + 1, 5).Value Then
                'formulas:
                .Range(.Cells(i, 15), .Cells(i, 18)).Formula = Array("=SUM(M" & iSrt & ":M" & i & ")", _
                                        "=IF(G" & i & "=0,"""",IF((O" & i & "/G" & i & ">=90%),"""",O" & i & "-(G" & i & "*0.9)))", _
                                        "=IF(G" & i & "=0,"""",IF((O" & i & "/G" & i & ">100%), O" & i & "-G" & i & ",""""))", _
                                        "=Count(M" & iSrt & ":M" & i & ")")
                
                'backcolor:
                .Range("A" & iSrt & ":R" & i).Interior.ColorIndex = clrSet
                If clrSet = clr1 Then clrSet = clr2 Else clrSet = clr1
                iSrt = i + 1
            End If
        Next i
    End With
End Sub