Hong Kong (full name, Hong Kong Special Administrative Region) is a special administrative region of China covering an area of approximately 1,100 sq km. Although it is part of China, Hong Kong is governed under the "one country, two systems" principle, under which it has a large degree of autonomy. Its terrain is hilly to mountainous with lowlands in the north. Hong Kong borders China, and has 733 km of coastline. The currency is the Hong Kong dollar, and exports include electrical machinery, textiles, apparel, footwear, watches and clocks, toys, plastics, precious stones and printed material. The population of approximately 7,000,000 people comprises an ethnic makeup that is 95% Chinese. The primary language is Cantonese, and the religion is 90% indigenous, 10% Christian.