Question: when is the last time a us team won the little league world series
[{'answer': '2018', 'provenance': [{'wikipedia_id': '674587', 'title': 'Little League World Series', 'start_paragraph_id': 7, 'start_character': 636, 'end_paragraph_id': 7, 'end_character': 640, 'bleu_score': 1.0, 'section': 'Section::::Qualifying tournaments.\n'}]}]