Sub Corrige()
Dim N As Range, P As Range, R As Range, a1$, a2$
Set N = [A2:A26]: Set P = [B2:B26] 'plages à adapter
Set R = [I2:I26] 'plage des résultats, à adapter
a1 = Application.ConvertFormula(N.Address, xlA1, xlR1C1)
a2 = Application.ConvertFormula(P.Address, xlA1, xlR1C1)
R.NumberFormat = "0%"'format à adapter
R.FormulaR1C1 = "=RC2/SUMIF(" & a1 & ",RC1," & a2 & ")"
R = R.Value 'ne garde que les valeurs
End Sub