suffer losses as a result of natural disasters; and it has played the leading role in the exploration of space, which is too expensive for private enterprise to handle. In this mixed economy, individuals can help guide the economy not only through the choices they make as consumers but through the votes they cast for officials who shape economic policy. In recent years, consumers have voiced concerns about product safety, environmental threats posed by certain industrial practices, and potential health risks citizens may face; government has responded by creating agencies to protect consumer interests and promote the general public welfare. The U.S. economy has changed in other ways as well. The population and the labor force have shifted dramatically away from farms to cities, from fields to factories, and, above all, to service industries. In today's economy, the providers of personal and public services far outnumber producers of agricultural and manufactured goods. As the economy has grown more complex, statistics also reveal over the last century a sharp long-term trend away from self-employment toward working for others.