Since initiating market reforms in 1978, China has shifted from a centrally-planned to a more market-based economy and has experienced rapid economic and social development. GDP growth has averaged nearly 10 percent a year--the fastest sustained expansion by a major economy in history--and has lifted more than 800 million people out of poverty. China reached all the Millennium Development Goals (MDGs) by 2015 and made a major contribution to the achievement of the MDGs globally. Although China's GDP growth has gradually showed since 2012, it is still impressive by current global standards. With a population of 1.3 billion, China is the second largest economy and is increasingly playing an important and influential role in development and in the global economy. China has been the largest single contributor to world growth since the global financial crisis of 2008. Yet China remains a developing country (its per capita income is still a fraction of that in advanced countries) and its market reforms are incomplete. According to China's current poverty standard (per capita rural net income of RMB 2,300 per year in 2010 constant prices), there were 55 million poor in rural areas in 2015. Rapid economic ascendance has brought on many challenges as well, including high inequality; rapid urbanization; challenges to environmental sustainability; and external imbalances. China also faces demographic pressures related to an aging population and the internal migration of labor. Significant policy adjustments are required in order for China's growth to be sustainable. Experience shows that transitioning from middle-income to high-income status can be more difficult than moving up from low to middle income.