Less than 2% of these imports are inspected by the USDA. Natural gas is the largest source of energy produced in the US followed by coal, oil, renewable and nuclear. (As of 2011) 26 percent of energy used in homes is for lighting and other appliances Genetically engineered soybeans, corn and cotton in the US make up 93%, 88% and 94% of the total acreage of each respective crop.