Question: when was the egg mcmuffin added to the menu
[{'answer': '1972', 'provenance': [{'wikipedia_id': '6364031', 'title': 'McMuffin', 'start_paragraph_id': 1, 'start_character': 176, 'end_paragraph_id': 1, 'end_character': 180, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6364031', 'title': 'McMuffin', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 115, 'bleu_score': 0.8970773746801091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17810962831688883991}, 'section': 'Section::::History.\n'}]}]