VBA code to fill missing data

[SamT]

Sub fillAwithB_regressive() 
    Dim rw As Long 
    With Sheets("Sheet?") 'Edit as needed
for rw = 1To Cells(Rows.Count, "B").End(xlUp).Row 
            If Cells(rw, "A") = "" Then Cells(rw, "A") = Cells(rw, "B") * .07 + 10 
        Next rw 
    End With 
End Sub