Question: how much energy does coal produce in the us
[{'answer': '30.4 %'}, {'answer': '16.5 quadrillion BTUs'}, {}, {'provenance': [{'wikipedia_id': '13928121', 'title': 'Coal power in the United States', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 602, 'bleu_score': 0.979484453366057, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 20971327815458667}, 'section': 'Section::::Trends, comparisons, and forecasts.\n'}]}, {'provenance': [{'wikipedia_id': '30831536', 'title': 'United States energy building codes', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['ide by codes to ensure efficiency. Using more efficient methods and materials upfront when constructing the buildings will help to cut down on energy usage. There are building energy codes fo', 'The United States building codes related to energy are energy codes and standards that set minimum requirements for energy-efficient design and construction for new and renovated buildings that impact energy use and emissions for the life of the building. Buildings account for 39% of United States energy use, two-thirds of electricity, and one-eighth of water. With buildings being such a main source of energy usage in the United States, along with the surrounding issues associated with high energy usage it is imperative that buildings abide by codes to ensure efficiency. Using more efficient methods and materials upfront when constructing the buildings will help to cut down on energy usage. There are building energy codes for both commercial and residential buildings.']}}]}]