Finding database backup size difference with period.

I have found a very good link to find backup size difference during daily or monthly changes.

-- Transact-SQL script to analyse the database size growth using backup history.
DECLARE @startDate datetime;
SET @startDate = GetDate();

SELECT PVT.DatabaseName
      , PVT.[0], PVT.[-1], PVT.[-2], PVT.[-3],  PVT.[-4],  PVT.[-5],  PVT.[-6]
               , PVT.[-7], PVT.[-8], PVT.[-9], PVT.[-10], PVT.[-11], PVT.[-12]
FROM
   (SELECT BS.database_name AS DatabaseName
          ,DATEDIFF(mm, @startDate, BS.backup_start_date) AS MonthsAgo
          ,CONVERT(numeric(10, 1), AVG(BF.file_size / 1048576.0)) AS AvgSizeMB
    FROM msdb.dbo.backupset as BS
         INNER JOIN
         msdb.dbo.backupfile AS BF
             ON BS.backup_set_id = BF.backup_set_id
    WHERE NOT BS.database_name IN
              ('master', 'msdb', 'model', 'tempdb')
          AND BF.[file_type] = 'D'
          AND BS.backup_start_date BETWEEN DATEADD(yy, -1, @startDate) AND @startDate
    GROUP BY BS.database_name
            ,DATEDIFF(mm, @startDate, BS.backup_start_date)
    ) AS BCKSTAT
PIVOT (SUM(BCKSTAT.AvgSizeMB)
       FOR BCKSTAT.MonthsAgo IN ([0], [-1], [-2], [-3], [-4], [-5], [-6], [-7], [-8], [-9], [-10], [-11], [-12])
      ) AS PVT
ORDER BY PVT.DatabaseName;