power query code that count duplicates on multicolumn data

Need help on correcting this code to count duplicates this duplicate of current row against all rows.  Any help is appreciated

Table.AddColumn(Source, "Add",
each List.Count(
Table.SelectRows(
    Source,
    (C) => List.Intersect(Table.ToList(Source),C(Table.ToList(Source)))=5
)[Column1]
))