Question: when did interracial marriage become legal in the united states
[{'answer': '1967', 'provenance': [{'wikipedia_id': '3872186', 'title': 'Interracial marriage', 'start_paragraph_id': 2, 'start_character': 146, 'end_paragraph_id': 2, 'end_character': 150, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]