The main results of the survey on population fluctuations and family planning as of April 1, 2025 ; ; The book consists of 4 parts: Part I: Key Results: Presents the main results of the survey along with analyses of population size and structure, marital status, education, family planning and reproductive health, fertility rates, mortality, migration and basic characteristics of migrants; Part II: Aggregated Tables: Provides users with the most basic aggregate data tables (more detailed figures as needed can be compiled from the survey's micro-database Part III: Survey design and organization: Describe the process of organizing the investigation; Survey sample design and estimation: sample selection, sample size determination and sample allocation, sample magnification weight estimation; some concepts and definitions of population fluctuation and family planning indicators; Part IV: Appendices: Includes appendices on necessary contents to supplement the main content of the book