Question: when did the first avengers movie come out
[{'answer': '2012', 'provenance': [{'wikipedia_id': '42163310', 'title': 'List of Marvel Cinematic Universe films', 'start_paragraph_id': 3, 'start_character': 366, 'end_paragraph_id': 3, 'end_character': 370, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]