China had one of the largest economies in the world for most of the past two thousand years, during which it has seen cycles of prosperity and decline. Since economic reforms began in 1978, China has developed into a highly diversified economy and one of the most consequential players in international trade. Major sectors of competitive strength include manufacturing, retail, mining, steel, textiles, automobiles, energy generation, green energy, banking, electronics, telecommunications, real estate, e-commerce, and tourism. China has three out of the ten largest stock exchanges in the world—Shanghai, Hong Kong and Shenzhen—that together have a market capitalization of over $15.9 trillion, as of October 2020. China has four (Shanghai, Hong Kong, Beijing, and Shenzhen) out of the world's top ten most competitive financial centers, which is more than any country in the 2020 Global Financial Centres Index. By 2035, China's four cities (Shanghai, Beijing, Guangzhou and Shenzhen) are projected to be among the global top ten largest cities by nominal GDP according to a report by Oxford Economics.