Question: when did the nfl change to a 16 game schedule
[{'answer': '1978', 'provenance': [{'wikipedia_id': '7990664', 'title': 'NFL regular season', 'start_paragraph_id': 16, 'start_character': 460, 'end_paragraph_id': 16, 'end_character': 464, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '7990664', 'title': 'NFL regular season', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 523, 'bleu_score': 0.856140342975479, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 906720178965654478}, 'section': 'Section::::History.\n'}]}]