How to limit the results on a percentage rather than fix limit numer in mysql? : The below mysql question returns only the 10 first rows. How can I limit the them to 10% of all?

    SELECT page, 
           poso, 
           diff 
    FROM   (SELECT page, 
                   Count(*) AS poso, 
                   ( Sum(Date(timestamp) = Curdate()) - Sum( 
                     Date(timestamp) = Date_sub(Curdate(), 
                                       INTERVAL 1 day)) ) 
                            diff 
            FROM   `behaviour` 
            WHERE  Date(timestamp) >= Date_sub(Curdate(), INTERVAL 1 day) 
            GROUP  BY page 
            ORDER  BY ( Sum(Date(timestamp) = Curdate()) - Sum( 
                        Date(timestamp) = Date_sub(Curdate(), 
                                   INTERVAL 1 day)) 
                      ) DESC 
            LIMIT  10) AS u 
    ORDER  BY diff DESC 