Because of this and a high unemployment rate, many people have left the kingdom. There are a few manufacturing enterprises, mostly food processing. Tourism has begun to increase significantly. Petroleum was discovered around Tongatapu in the late 1970s. Tonga has a constitutional monarchy.
Executive authority is vested in the monarch, a privy council, and the cabinet.
A one-house legislature represents both nobles and commoners. Judges are appointed by the monarch. Primary education is compulsory between the ages of 6 and 14, and the government schools are free. There are secondary schools, several vocational and technical schools, and a teacher training college. The first European to visit Tonga was Dutch navigator Jakob Le Maire in 1616.