Question: when did stink bugs come to the us
[{'answer': '1998', 'provenance': [{'wikipedia_id': '9186134', 'title': 'Brown marmorated stink bug', 'start_paragraph_id': 2, 'start_character': 344, 'end_paragraph_id': 2, 'end_character': 348, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]