Bonjour à tous !
Une proposition via Power Query :
let
Source = Excel.CurrentWorkbook(){[Name="Tableau1"]}[Content],
Ajt_Ratio = Table.AddColumn(Source, "Ratio", each [QTE] / List.Sum(Source[QTE])),
#"Type%" = Table.TransformColumnTypes(Ajt_Ratio,{{"Ratio", Percentage.Type}})
in
#"Type%"