Common law is a body of laws that are based on the history of court rulings in a particular area. The rulings have the same weight as other laws, such as statutes and regulations. In the world, there are two major types of law systems. The United States and a number of other countries rely on a blend of common law and civil law. Common law systems govern nearly 30 percent of the world's population. The approach is often known as case law or precedence because it is developed over time by the decisions of the courts. Common law is the rule of thumb in England, and it affects many of the United States' laws. For example, the United States Supreme Court hears cases on a regular basis, and their decisions affect future decisions and laws. Common law systems place emphasis on court rulings, and the verdicts have the same force as a law, statute or regulation in a civil law system.