Question: when did the us first start using drones
[{'answer': '1918', 'provenance': [{'wikipedia_id': '3524423', 'title': 'History of unmanned aerial vehicles', 'start_paragraph_id': 8, 'start_character': 217, 'end_paragraph_id': 8, 'end_character': 221, 'bleu_score': 1.0, 'section': 'Section::::Early development.:World War I.\n'}]}, {'provenance': [{'wikipedia_id': '3524423', 'title': 'History of unmanned aerial vehicles', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 379, 'bleu_score': 0.9699161750394991, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3323027143531390443}, 'section': 'Section::::Early development.:World War I.\n'}]}]