Question: when did curling become a winter olympic sport
[{'answer': '1998', 'provenance': [{'wikipedia_id': '3092138', 'title': 'Curling at the Winter Olympics', 'start_paragraph_id': 1, 'start_character': 385, 'end_paragraph_id': 1, 'end_character': 389, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3092138', 'title': 'Curling at the Winter Olympics', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 402, 'bleu_score': 0.970362113628587, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13730232671713649061}, 'section': 'Section::::Abstract.'}]}]