U.S.-China economic ties have expanded substantially over the past several years. Total U.S.-China trade, which totaled only $5 billion in 1980, rose to $387 billion in 2007. China overtook Japan to become the third largest U.S. export market, and overtook Canada to become the largest source of U.S. imports. With a huge population and a rapidly expanding economy, China is a potentially huge market for U.S. exporters. However, U.S.-China economic relations have become strained over a number of issues, including large and growing U.S. trade deficits with China (which hit $256 billion in 2007), China s failure to fully implement its World Trade Organization (WTO) commitments (especially in regards to protection of intellectual property rights), its refusal to adopt a floating currency system, its use of industrial policies and other practices deemed unfair and/or harmful to various U.S. economic sectors, and failure to ensure that its exports to the United States meet U.S. health and safety standards.