Question: when were kinder eggs banned in the us
[{'answer': '1997', 'provenance': [{'wikipedia_id': '46839', 'title': 'Kinder Surprise', 'start_paragraph_id': 18, 'start_character': 3, 'end_paragraph_id': 18, 'end_character': 7, 'bleu_score': 1.0, 'section': 'Section::::Safety concerns.:United States.\n'}]}, {'provenance': [{'wikipedia_id': '46839', 'title': 'Kinder Surprise', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 550, 'bleu_score': 0.978375183951072, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9658117776415897404}, 'section': 'Section::::Safety concerns.:United States.\n'}]}]