Why is everyone trying to infer net new births from fertility rates? We have the exact data: https://dof.ca.gov/wp-content/uploads/Forecasting/Demographics/Docu

Why is everyone trying to infer net new births from fertility rates? We have the exact data: https://dof.ca.gov/wp-content/uploads/Forecasting/Demographics/Documents/E-2_Report_July-2010-2021_w.xlsx https://dof.ca.gov/wp-content/uploads/Forecasting/Demographi... People can live longer, and natural population increase can persist long after fertility drops below replacement.