China's socialist market economy is the world's second largest economy by nominal GDP, and the world's largest economy by purchasing power parity according to the IMF, although China's National Bureau of Statistics rejects this claim. Until 2015 China was the world's fastest-growing major economy, with growth rates averaging 10% over 30 years, until it was surpassed by neighbouring India. Due to historical and political facts of China's developing economy, China's public sector accounts for a bigger share of the national economy than the burgeoning private sector.