Automatically generate columns in Power Query

Hi snowrider1799 ,

something like this:

let
  Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("NcvJDcBACEPRXjiP5LBFSS2I/tsIMJnb15MdQQIGO60dL+UKcvgxOTb5lGmFXGPWu7aO324omMsm9ldhYJuv9SHzAw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"File Date" = _t, #"Expiry Date" = _t]),
  #"Changed Type" = Table.TransformColumnTypes(Source, {{"File Date", type date}, {"Expiry Date", type date}}),
  // Plug in your source table here
  SourceTable = #"Changed Type",
  // This builds a list of years from the data
  ListOfYearsUsed = List.Sort(List.Transform(List.Combine({SourceTable[File Date], SourceTable[Expiry Date]}), Date.Year)),
  // Please feel free to replace with manual year range which looks like {2010..2020}
  ListOfYears = {ListOfYearsUsed{0}..List.Last(ListOfYearsUsed)},
  // This cycles through the list of years and add columns for each year
  #"Added Custom" = List.Accumulate(ListOfYears, SourceTable, (a, n)=> Table.AddColumn(a, Text.From(n), each if Date.Year([File Date]) <= Number.From(n) and Date.Year([Expiry Date]) > Number.From(n) then 1 else null, type number)),
  
  // This generates list parameter for Table.Group
  Parameters = List.Accumulate(ListOfYears, {}, (a,n)=> a & {{Text.From(n), (x)=> List.Sum(Table.Column(x, Text.From(n))), type number}}),
  #"Grouped rows" = Table.Group(#"Added Custom", {"Expiry Date"}, Parameters)
in
  #"Grouped rows"

NB: change "Expiry Date" in the #"Grouped rows" to "Ultimate Parent" as per your screenshot.

Kind regards,

JB