                                                    

40                    

   

11   18             

                 

                

          19     

  6729             

       

20—30   30—40   40       

               

   47.76%  51.95%  52.23%       

            

    20—30   30—40   40     

    18.63%  59.74%  75.95%  

              

               

    >>>