Question: when did the post office start using zip codes
[{'answer': 'July 1 , 1963', 'provenance': [{'wikipedia_id': '51550', 'title': 'ZIP Code', 'start_paragraph_id': 10, 'start_character': 125, 'end_paragraph_id': 10, 'end_character': 138, 'bleu_score': 1.0, 'section': 'Section::::History.:Early history and five-digit ZIP Codes.\n'}]}, {'provenance': [{'wikipedia_id': '51550', 'title': 'ZIP Code', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 1030, 'bleu_score': 0.936187243340811, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5453235346946104577}, 'section': 'Section::::History.:Early history and five-digit ZIP Codes.\n'}]}]