Approximately how long ago did stage 4 end and stage 5 begin?

Answer 1

Stage 4 of demographic transition typically refers to a period of low birth and death rates, characterized by a stable population. This stage is often associated with developed countries and has been prevalent since the mid-20th century. Stage 5, which includes declining birth rates leading to potential population decrease, is a more recent phenomenon that has emerged in some countries over the last few decades. Thus, stage 4 ended and stage 5 began roughly in the late 20th to early 21st century.