This dimension groups regions by how many people live within them. World population growth itself has been strikingly uneven over time, since Wikipedia notes "it took around 300,000 years of human prehistory and history for the human population to reach a billion and only 218 more years from there to reach 8 billion," and a region's own population reflects that same long, uneven history of settlement. Browsing by population band separates densely settled regions from sparsely populated ones.