Question: when was the national mall in washington dc built
[{'answer': '1815', 'provenance': [{'wikipedia_id': '167796', 'title': 'National Mall', 'start_paragraph_id': 9, 'start_character': 40, 'end_paragraph_id': 9, 'end_character': 44, 'bleu_score': 1.0, 'section': "Section::::History.:L'Enfant City Plan.\n"}]}, {'provenance': [{'wikipedia_id': '167796', 'title': 'National Mall', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 502, 'bleu_score': 0.7587120651825771, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15129205975186005841}, 'section': "Section::::History.:L'Enfant City Plan.\n"}]}]