Which year had the highest total population, 1950 or 1900?
return 1950 ;return 1900 ;return populations of #1 ;return populations of #2 ;return sum of #3 ;return sum of #4 ;return which is the  highest of #5 ,  #6
['select', 'select', 'project', 'project', 'aggregate', 'aggregate', 'comparison']