Question: when did they start putting barcodes on products
[{'answer': 'July 1972 ,', 'provenance': [{'wikipedia_id': '60600', 'title': 'Barcode', 'start_paragraph_id': 22, 'start_character': 3, 'end_paragraph_id': 22, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::History.:Universal Product Code.\n'}]}, {'provenance': [{'wikipedia_id': '60600', 'title': 'Barcode', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 703, 'bleu_score': 0.9556930541639581, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5643050275138368868}, 'section': 'Section::::History.:Universal Product Code.\n'}]}]