Question: when did the nba change the playoff series
[{'answer': '2016', 'provenance': [{'wikipedia_id': '12106552', 'title': 'NBA playoffs', 'start_paragraph_id': 3, 'start_character': 96, 'end_paragraph_id': 3, 'end_character': 100, 'bleu_score': 1.0, 'section': 'Section::::Format.\n'}]}, {'provenance': [{'wikipedia_id': '12106552', 'title': 'NBA playoffs', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 465, 'bleu_score': 0.9754554449993441, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7450100409882515826}, 'section': 'Section::::Format.\n'}]}]