Germany and Japan have the world’s oldest populations. Niger has the youngest
Much of what looks like politics and economics is actually just demographics in disguise. Country’s with aging populations often end up with high budget deficits and weak economic growth because there are too few workers to support the many retirees. Countries with extremely young populations often end up in political chaos — particularly if there aren’t enough jobs to go around. Right now, Germany and Japan have the world’s oldest populations, with a median age of 46.1. Niger has the world’s youngest population with a median age of 15.1.
Source: Ezra Klein, ”22 maps and charts that will surprise you,” Vox, Sept. 23, 2014