evidence: In 1989, there were protests such those in Tiananmen Square, and then throughout the entire nation.[117] Zhao Ziyang was put under house arrest for his sympathies to the protests and was replaced by Jiang Zemin. Jiang continued economic reforms, closing many SOEs and trimming down "iron rice bowl" (life-tenure positions).[118][119][120] China's economy grew sevenfold during this time.[118] British Hong Kong and Portuguese Macau returned to China in 1997 and 1999, respectively, as special administrative regions under the principle of one country, two systems. The country joined the World Trade Organization in 2001.[118] [...] The PRC is constitutionally a unitary state divided into 23 provinces,[u] five autonomous regions (each with a designated minority group), and four direct-administered municipalities—collectively referred to as "mainland China"—as well as the special administrative regions (SARs) of Hong Kong and Macau.[204] The PRC regards the island of Taiwan as its Taiwan Province, Kinmen and Matsu as a part of Fujian Province and islands the ROC controls in the South China Sea as a part of Hainan Province and Guangdong Province, although all these territories are governed by the Republic of China (ROC).[205][33] Geographically, all 31 provincial divisions of mainland China can be grouped into six regions: North China, East China, Southwestern China, Northwestern China, South Central China, and Northeast China.[206]