Plot of High*Year.  Symbol used is '*'.             
            Plot of Low*Year.   Symbol used is 'o'.             
                                                                
      ---+---------+---------+---------+---------+---------+--- 
 4000 +                                              *        + 
      |                                             *         | 
      |                                            * o        | 
      |                                           *oo         | 
 High |                                          *            | 
      |                                       * *             | 
      |                                           o           | 
      |                                        *oo            | 
 2000 +                                      * o              + 
      |                                       o               | 
      |                                     *o                | 
      |                                   **o                 | 
      |                ****** ************oo                  | 
      |           *****oooooo*o o oooooooo                    | 
      |      *****oooo           o                            | 
      |      o                                                | 
    0 +                                                       + 
      ---+---------+---------+---------+---------+---------+--- 
       1950      1960      1970      1980      1990      2000   
                                                                
                                Year                            
                                                                
NOTE: 7 obs hidden.