             1947                                                     18                                                                                                 1979                          10       

     1                                           
     2                                                                 
     3                                                                
      4                                           
      5                                           
      6                                            
      7                                    
      8                                                                      
      9                                      

     10                                                   

                                                                                                                                    20%  30%                                                                                                                                                                                                90%        