Which year had signed more PACS, 2003 or 2004?
return PACS signed ;return #1 of year 2003 ;return #1 of year 2004 ;return number of  #2 ;return number of  #3 ;return which is highest of #4 ,  #5
['select', 'filter', 'filter', 'aggregate', 'aggregate', 'comparison']