Demographic Trends and Population Policy 27 61. In 1980 an average brigade had a population of about 1,150. See Dwight Perkins and ShahidYusuf, 1984, p. 93. 62. Ansley J. Coale, The Population Trends, Population Policy and Population Studies in China', Population and Development Review, Vol. 7, No. 1, March 1981, pp. 75-89. 63. Lue Zheng, 'Population' in Yu Guangyuan, China's Socialist Modernisation, Foreign Languages Press, Beijing, 1984, p. 550. 64. Zhao Ziyang, 'Report on the Seventh Five-Year Plan' The Fourth Session of the Sixth National People's Congress : Main Documents, Foreign Languages Press, Beijing, 1986, pp. 13, 32-34