Question: where are the highest average incomes found in north america
[{'answer': 'Virginia', 'provenance': [{'wikipedia_id': '1979455', 'title': 'List of highest-income counties in the United States', 'start_paragraph_id': 4, 'start_character': 16, 'end_paragraph_id': 4, 'end_character': 24, 'bleu_score': 1.0, 'section': 'Section::::Summary.\n'}]}, {'provenance': [{'wikipedia_id': '1979455', 'title': 'List of highest-income counties in the United States', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6286796743296557189}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1979455', 'title': 'List of highest-income counties in the United States', 'section': 'Section::::Summary.\n', 'start_paragraph_id': 4, 'end_paragraph_id': 4, 'meta': {'evidence_span': ['Virginia, ranks as the highest-income county by median family income.', 'Fairfax County, Virginia, a suburb of Washington, D.C., is the highest-income county by median household income. Another Washington suburb, Arlington County, Virginia, ranks as the highest-income county by median family income.', 'Fairfax County, Virginia, a suburb of Washington, D.C., is the highest-income county by median household income. Another Washington suburb, Arlington County, Virginia, ranks as the highest-income county by median family income.']}}]}]