Zhang Yaoguang1, Wu Shiyong1, Wang Shuai1, Yao Qiang2, Zhu Jiming3
1 Center for Health Statistics and Information, National Health Commission of People′s Republic of China, Beijing 100810, China;
2 School of Political Science &Public Administration, Wuhan University, Wuhan 430072, China;
3 Vanke School of Public Health, Tsinghua University, Beijing 100084, China