Find position number for each group (Table.PositionOf() with Table.Group) in Power Query (M language)

I'd like to find number of position first "TAK" in column "taknie" fo开发者_开发问答r each group (column Grupa).

This is my table.

I've tried in Advanced editor

let
    Source = Excel.CurrentWorkbook(){[Name="Tabela1"]}[Content],
    Grupa = Table.Group(Source, "Grupa", {"wynik", each Table.PositionOf(
        Source, 
        [taknie = "TAK"], 
        Occurrence.First,
        "taknie"
    ) + 1})
in
    Grupa

but it doesn't work properly:

enter image description here

Instead of 2, 2, 2, 2, 2, should be