Question: when was the olive tree introduced to north america
[{'answer': '1838', 'provenance': [{'wikipedia_id': '22479', 'title': 'Olive', 'start_paragraph_id': 33, 'start_character': 593, 'end_paragraph_id': 33, 'end_character': 597, 'bleu_score': 1.0, 'section': 'Section::::History.:Outside the Mediterranean.\n'}]}, {'provenance': [{'wikipedia_id': '22479', 'title': 'Olive', 'start_paragraph_id': 33, 'start_character': 0, 'end_paragraph_id': 33, 'end_character': 1148, 'bleu_score': 0.9894455409323081, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10158916242990916387}, 'section': 'Section::::History.:Outside the Mediterranean.\n'}]}]