Voilà.
let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtQ31DcyMDJSUNJRciwoyEkFMcwVlGJ1UOU8AkCkCUTCCJsmC0w5iCZLiIQxNk2GBpiSEF1gmVgA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Report Date" = _t, Company = _t, Number = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Report Date", type date}, {"Company", type text}, {"Number", Int64.Type}}),
#"Grouped Rows" = Table.Group(#"Changed Type", {"Company"}, {{"All", each _, type table [Report Date=nullable date, Company=nullable text, Number=nullable number]}}),
#"Added Custom" = Table.AddColumn(#"Grouped Rows", "Custom", each
let a = Table.Sort([All], {{"Report Date", Order.Descending}}),
b = Table.AddIndexColumn(a, "index"),
c = Table.AddColumn(b, "Status", each if [index] = 0 then "Current" else if [index] = 1 then "Prior" else null )
in c
),
#"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Company", "All"}),
#"Expanded Custom" = Table.ExpandTableColumn(#"Removed Columns", "Custom", {"Report Date", "Company", "Number", "index", "Status"}, {"Report Date", "Company", "Number", "index", "Status"}),
#"Removed Columns1" = Table.RemoveColumns(#"Expanded Custom",{"index"})
in
#"Removed Columns1"