Getting total sum per Month and get average per month per category

netteSJ,

Starting with columns Company, Date and Parameters here is method for Power Query.

1. Transform the “Date” column to start of month and rename as “Month Starting”.
2. Add a column called “Count”, with all rows containing 1.
3. Pivot the “Parameters” column using the “Count” column as the values column.
4. Replace nulls with zeroes.
5. Group by company and start of month.
6. Add a column for total observations.
7. Add a column for percentage at risk.
8. Add a column for percentage safe.

The NaNs occur when Total Observations are zero. You may wish to filter out those rows, add some test code for zeroes or replace NaN with some text like N/A.

Here is my sample data

...here is the result

...and here is the M code

let
   Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
   #"Changed Type" = Table.TransformColumnTypes(Source,
      {{"Company", type text}, {"Date", type datetime}, {"Parameters", type text}}),
   #"Calculated Start of Month" = Table.TransformColumns(#"Changed Type",
      {{"Date", Date.StartOfMonth, type datetime}}),
   #"Rename Columns to Start of Month" = Table.RenameColumns(#"Calculated Start of Month",
      {{"Date", "Month Starting"}}),
   #"Add Count" = Table.AddColumn(#"Rename Columns to Start of Month", 
      "Count", 
      each 1, 
      Int64.Type),
   #"Pivot Parameters Column" = Table.Pivot(#"Add Count", 
      List.Distinct(#"Add Count"[Parameters]), 
      "Parameters", 
      "Count", 
      List.Sum),
   #"Replace nulls with Zeroes" = Table.ReplaceValue(#"Pivot Parameters Column",
      null,
      0,
      Replacer.ReplaceValue,
      {"Safe", "At Risk", "-"}),
   #"Group by Company and Month Starting" = Table.Group(#"Replace nulls with Zeroes", 
      {"Company", "Month Starting"}, 
      {
         {"Safe", each List.Sum([Safe]), type nullable number}, 
         {"At Risk", each List.Sum([At Risk]), type nullable number}
      }),
   #"Add Total Observations" = Table.AddColumn(#"Group by Company and Month Starting", 
      "Total Observations", 
      each [Safe] + [At Risk],
      Int64.Type),
   #"Add % At Risk" = Table.AddColumn(#"Add Total Observations", 
      "% At Risk", 
      each [At Risk] / [Total Observations], 
      Percentage.Type),
   #"Add % Safe" = Table.AddColumn(#"Add % At Risk", 
      "% Safe", 
      each [Safe] / [Total Observations],
      Percentage.Type)
in
   #"Add % Safe"