Question: when did the us quit making silver coins
[{'answer': 'July 23 , 1965', 'provenance': [{'wikipedia_id': '10566622', 'title': 'Coinage Act of 1965', 'start_paragraph_id': 28, 'start_character': 619, 'end_paragraph_id': 28, 'end_character': 633, 'bleu_score': 1.0, 'section': 'Section::::Legislation.\n'}]}, {'provenance': [{'wikipedia_id': '10566622', 'title': 'Coinage Act of 1965', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1238, 'bleu_score': 0.9904531874107041, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9655777530497638466}, 'section': 'Section::::Abstract.'}]}]