The VARIABLES= suboption specifies the variables to write to the data component and the order in which to write them. The suboption includes attribute specifications of a label (for the variable Type) and a format (for the variable Kilotons). The label specified here takes precedence over the LABEL statement assignment that was made previously in the DATA step, so it is used as the column header for Type. 
           variables=(country
                      type(label='Type of Grain')
                      kilotons(format=comma12.))
      );