Question: when did abba win the eurovision song contest
[{'answer': '1974', 'provenance': [{'wikipedia_id': '2212439', 'title': 'List of Eurovision Song Contest winners', 'start_paragraph_id': 3, 'start_character': 512, 'end_paragraph_id': 3, 'end_character': 516, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2212439', 'title': 'List of Eurovision Song Contest winners', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 804, 'bleu_score': 0.9570764685495211, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16305513796427126857}, 'section': 'Section::::Abstract.'}]}]