evidence: Colonized by the Portuguese in the 16th century, Macau was the first European settlement in the Far East. Pursuant to an agreement signed by China and Portugal on 13 April 1987, Macau became the Macau Special Administrative Region of the People's Republic of China on 20 December 1999. In this agreement, China promised that, under its "one country, two systems" formula, China's political and economic system would not be imposed on Macau, and that Macau would enjoy a "high degree of autonomy" in all matters except foreign affairs and defense for the subsequent 50 years. [...] Constitution history: previous 1976 (Organic Statute of Macau, under Portuguese authority); latest adopted 31 March 1993, effective 20 December 1999 (Basic Law of the Macau Special Administrative Region of the People's Republic of China serves as Macau's constitution) [...] Since opening up its locally-controlled casino industry to foreign competition in 2001, Macau has attracted tens of billions of dollars in foreign investment, transforming the territory into one of the world's largest gaming centers. Macau's gaming and tourism businesses were fueled by China's decision to relax travel restrictions on Chinese citizens wishing to visit Macau. In 2016, Macau's gaming-related taxes accounted for more than 76% of total government revenue.