Question: when did social security began in the united states
[{'answer': '1935', 'provenance': [{'wikipedia_id': '48728', 'title': 'Social Security (United States)', 'start_paragraph_id': 1, 'start_character': 291, 'end_paragraph_id': 1, 'end_character': 295, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]