Pakistan

With a median age of just 22.7 years, the country's demographic trajectory is markedly younger than Nigeria's median of 18.1 years, fueling continued expansion. This rapid growth positions Pakistan to become the fourth-most populous nation worldwide by mid-century, adding roughly 4.5 million people annually. The population density of 287 people per square kilometer underscores the pressure on infrastructure, yet the fertility rate of 3.4 births per woman remains above replacement level. Without significant economic shifts, Pakistan's momentum will likely reshape regional demographics, outpacing slower-growing neighbors like Bangladesh.