Question: when was pole vault introduced in olympics games
[{'answer': '1896', 'provenance': [{'wikipedia_id': '42654536', 'title': 'Pole vault at the Olympics', 'start_paragraph_id': 1, 'start_character': 234, 'end_paragraph_id': 1, 'end_character': 238, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '42654536', 'title': 'Pole vault at the Olympics', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 474, 'bleu_score': 0.9470882598755391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14573528970086967721}, 'section': 'Section::::Abstract.'}]}]