While North Korea may not be on good terms with South Korea, the US, or Japan, it depends on trade with China. Last year, trade between China and the North was worth some $3.5 billion, up nearly 30 percent from 2009. Official exports include metals, wood products, vegetables, and clothing. Unofficial exports could include missiles, drugs, and trafficked persons. North Korea relies on China to send it everything from petroleum to plastics, and food to machinery.