Question: in the united states the main contributor to economic growth is due to the growth in
[{'answer': 'money supply', 'provenance': [{'wikipedia_id': '32022', 'title': 'Economy of the United States', 'start_paragraph_id': 14, 'start_character': 371, 'end_paragraph_id': 14, 'end_character': 383, 'bleu_score': 1.0, 'section': 'Section::::History.:20th century.\n'}]}, {'provenance': [{'wikipedia_id': '32022', 'title': 'Economy of the United States', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 704, 'bleu_score': 0.9826823455989031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12549005905295713098}, 'section': 'Section::::History.:20th century.\n'}]}]