A list of the top 8 countries by gross/total invoice size. List country name and gross invoice size.
return countries ;return gross/total invoice sizes of #1 ;return #1 where #2 is in  the  top 8 highest ;return names of #3 ;return gross/total invoice sizes of #3 ;return #4 ,  #5
['select', 'project', 'comparative', 'project', 'project', 'union']