Question: when did blackpool tower circus stop using animals
[{'answer': '1990', 'provenance': [{'wikipedia_id': '305175', 'title': 'Blackpool Tower', 'start_paragraph_id': 40, 'start_character': 37, 'end_paragraph_id': 40, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Tower Circus.\n'}]}, {'provenance': [{'wikipedia_id': '305175', 'title': 'Blackpool Tower', 'start_paragraph_id': 40, 'start_character': 0, 'end_paragraph_id': 40, 'end_character': 246, 'bleu_score': 0.953991849837532, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16132284152436688337}, 'section': 'Section::::Tower Circus.\n'}]}]