In just two decades, low-paid Chinese workers and a modernization-obsessed leadership have transformed China into one of the world's biggest economies. China produces two-thirds of the world's copiers, microwave ovens and DVD players, plus vast amounts of its clothing, shoes and toys. China's 9 percent growth rate over the past 25 years is the fastest economic acceleration in world history. Average incomes have quadrupled, and 300 million people were lifted out of poverty. China's $1.6 trillion economic output is expected to triple in 15 years, overtaking the United States by 2039. Critics say the communist nation owes much of its success to unfair trade practices and abysmal labor conditions for Chinese workers. In any case, China's leaders are intent on maintaining growth. High unemployment, widespread poverty and growing social unrest create unstoppable demand for the economy to keep expanding.