China has vowed to maintain the country's low birth rate in order to limit its population to within 1.39 billion by 2015. "From 2011 to 2015, the country's working-age population will peak, while the aging population will grow at an unprecedented rate," the State Council said in a policy document Tuesday. It added that the overall population growth rate will be kept below 0.72 percent per annum. The council sees these five years as "a major transitional period" for the population growth in China posing both opportunities and challenges, Xinhua reported. Also, the average life expectancy will reach 74.5, up one year from 2010. China's population is currently about 1.34 billion.