Price variation between dates

Hi Anonymous,

Assuming that the data is ordered by date:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("XdHLDcQwCATQXnyOCGDzcS1W+m9jV7CRYK9PyMzgcwbdSDcj87jGVlAez3UGV53gEjqrMqwduqoKoIVKn3UK1aobdIZaVQJaoV4VwTLD7rOSs4S9hmcNop6C8w3iHmNp8uxN3kdWD+K/ldJXcjYk7aezPAfZ3+082TvvPAi1lvZOM/bc8v2A5wM=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Brent = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Brent", type number}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Var", each 0, type number),
    ToList = Table.ToRecords(#"Added Custom"),
    Calculate = List.Accumulate(List.Skip(ToList), {List.First(ToList)}, (a,n)=> a & {Record.TransformFields(n,{"Var", (x)=> n[Brent] - List.Last(a)[Brent]})}),
    Output = Table.FromRecords(Calculate, Value.Type(#"Added Custom"))
in
    Output

Kind regards,

John