The United States courts of appeals are considered among the most powerful and influential courts in the United States. Because of their ability to set legal precedent in regions that cover millions of Americans, the United States courts of appeals have strong policy influence on U.S. law. Moreover, because the Supreme Court chooses to review fewer than 2% of the more than 7,000 to 8,000 cases filed with it annually, the U.S. courts of appeals serve as the final arbiter on most federal cases. The D.C. Circuit in particular is very influential, since it covers Washington, D.C., and thus covers Congress and many U.S. government agencies. The Ninth Circuit, which covers the entire west coast of the United States and contains 20% of the American population, is also an influential court.