Since the late 1970s, China has moved from a closed, centrally planned system to a more market-oriented one that plays a major global role. China has implemented reforms in a gradualist fashion, resulting in efficiency gains that have contributed to a more than tenfold increase in GDP since 1978. Reforms began with the phaseout of collectivized agriculture, and expanded to include the gradual liberalization of prices, fiscal decentralization, increased autonomy for state enterprises, growth of the private sector, development of stock markets and a modern banking system, and opening to foreign trade and investment. China continues to pursue an industrial policy, state-support of key sectors, and a restrictive investment regime. Measured on a purchasing power parity (PPP) basis that adjusts for price differences, China in 2016 stood as the largest economy in the world, surpassing the US in 2014 for the first time in modern history. China became the world's largest exporter in 2010, and the largest trading nation in 2013. Still, China's per capita income is below the world average.