Question: when was the last cricket world cup held
[{'answer': '2015', 'provenance': [{'wikipedia_id': '31384081', 'title': 'List of Cricket World Cup finals', 'start_paragraph_id': 2, 'start_character': 742, 'end_paragraph_id': 2, 'end_character': 746, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]