 Population estimates for world regions based on Maddison (2007), in millions.The row showing total world population includes the average growth rate per year over the period separating each column from the preceding one.When considering population estimates by world region, it is worth noting that population history of the indigenous peoples of the Americas before the 1492 voyage of Christopher Columbus has proven difficult to establish, with many historians arguing for an estimate of 50 million people throughout the Americas, and some estimating that populations may have reached 100 million people or more.