How should I free a class which uses a stringlist and and some strings Delphi

Question

I have a class which recurses through a number of files for keywords and builds a list of these keywords.

I have reduced the code to merely a shell but still get a memory leak - what am I doing wrong?

Uses Classes, SysUtils, StrUtils;

Type
  TKeywords = Class(TObject)
  private
    fIdentifiers: String;
    fDefines: String;
    fConstants: String;
    fSubroutines:  String;
    fProcedures: String;
    fParameters: String;
    fMacros: String;
    fAliases: String;
    fIncludes: TStringlist;
  public
    constructor Create;
    destructor Destroy;
    procedure Execute(pFileName: String);
    property Includes: TStringlist read fIncludes;
    property Identifiers: String read fIdentifiers;
    property Defines: String read fDefines;
    property Constants: String read fConstants;
    property Subroutines:  String read fSubroutines;
    property Procedures: String read fProcedures;
    property Parameters: String read fParameters;
    property Macros: String read fMacros;
    property Aliases: String read fAliases;
  end;

  var Keywords: TKeywords;

implementation

Constructor Tkeywords.Create;
begin
  inherited create;
  fIncludes := TStringlist.Create;
end;

Destructor TKeywords.Destroy;
begin
  fIncludes.Free;
  inherited destroy;
end;

procedure TKeywords.Execute(pFileName: string);
begin
  fIncludes.Add(pFileName);
end;

initialization
Keywords := Tkeywords.create;

finalization
Keywords.Free;

The memory leak reports: 1 x Unicodestring and 1 x StringList

Debug shows the destructor never gets called although it reaches Keywords.Free. Why is this?