Beijing ( CNN ) -- For the first time , urban dwellers in China now outnumber those living in the country . At the end of 2011 , China counted 690.79 million urban dwellers , the National Bureau of Statistics ( NBS ) said Tuesday . That marks an increase of 21 million over the previous year and accounts for 51.27 % of the country 's 1.347 billion people . During the same period , the rural population shrunk by 14.56 million to 656.56 million . The number of people between the ages of 15 and 64 stood at about 1 billion , or 74.4 % of the total population , the NBS added . China 's breakneck economic growth over the past three decades has seen an explosion in the size of China 's cities and towns , especially along its prosperous east coast . China 's economic growth slowing ? Spurred by Deng Xiaoping 's reform policies of the 1970s , which were aimed at modernizing an economy that had been dominated by agriculture , millions of Chinese farmers have been on the move , a massive internal migration that has changed the face of China . Many of these migrant workers , known as `` mingong , '' have left the countryside for the cities looking for better-paid jobs in areas such as manufacturing . Mega-cities like Shanghai , Beijing and Guangzhou , have been at the heart of this change , serving as the engines of China 's rapid economic transformation . `` Urbanization is an irreversible process and in the next 20 years , China 's urban population will reach 75 % of the total population , '' said Li Jianmin , head of the Institute of Population and Development Research at Nankai University , in quotes carried by Agence France-Presse . `` This will have a huge impact on China 's environment , and on social and economic development . '' There are at least 200 million migrant workers in the whole country , according to a national census carried out in April last year . Many are seasonal workers who work in cities part-time and then return to their villages -- though an increasing number live and work in urban centers permanently . However , it is difficult for many rural migrants working in cities to become fully-fledged urban residents , due to a centuries-old household registration system known as `` hukou , '' which categorizes the population into rural and urban residents . Without an urban hukou permit , a migrant is often denied access to the subsidized health , housing and education for children that city dwellers enjoy .
2011 : China counted 700 million urban dwellers , 200 million in rural areas . China 's breakneck economic growth has caused explosion in many of China 's cities . Many migrant workers , known as ` ` ##s , '' have left the countryside for the cities . Analyst : Urbanization is an irreversible process in the next 20 years .