PAPER: "Population aging caused by rise in sex ratio at birth."
AUTHORS: Zhen Zhang and Qiang Li

The data on mortality for plotting Figure 1 are available from the Human Mortality Database. The mortality and fertility rates used in simulations are taken from the United Nations World Population Prospects 2019, which is available in the R package "wpp2019" that can be downloaded from https://www.r-project.org/ or installed directly in R. The version of R used in this study is 4.0.2.

R code can be found in the three files: 
1. Functions.r provides several functions for calculating life tables, N(a,t), etc. 
2. Ratio.d2p.r is used to produce Figure 1. 
3. Simulations.r contains the codes for the simulations based on various scenarios (e.g., constant births, constant fertility, etc.) and those for plotting Figures 3-5.