Question: when did the united states annexed puerto rico
[{'answer': '1898', 'provenance': [{'wikipedia_id': '1216855', 'title': 'Puerto Rico Campaign', 'start_paragraph_id': 1, 'start_character': 167, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1216855', 'title': 'Puerto Rico Campaign', 'start_paragraph_id': 3, 'start_character': 3, 'end_paragraph_id': 3, 'end_character': 919, 'bleu_score': 0.634407495355862, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6254982585453080716}, 'section': 'Section::::Abstract.'}]}]