Question: when was the compton gamma ray observatory launched
[{'answer': '1991', 'provenance': [{'wikipedia_id': '543428', 'title': 'Compton Gamma Ray Observatory', 'start_paragraph_id': 1, 'start_character': 140, 'end_paragraph_id': 1, 'end_character': 144, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '543428', 'title': 'Compton Gamma Ray Observatory', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 613, 'bleu_score': 0.786976480684151, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18895291233546505}, 'section': 'Section::::Abstract.'}]}]