Population (n.) Other people, of whom there are always too many.
The prime minister of Belgium was visiting a West African country and touring with that country's prime minister. As they drove their convoy through the streets of the capital, the Belgian exclaimed, "But you have too many people here!" His peer replied, dryly, "Absolutely! Tell me which ones you don't like and I'll get rid of them."
It is explained by some economists that GDP divided by population = per capita income. The argument then follows that fewer people means more income. Thus, we get calls for birth control as an essential part of economic growth. There are two problems with this argument, one is ethical and one is scientific. The ethical argument is that "birth control" is invariably practiced by the powerful upon the weak. The scientific argument is as follows: "Where does that GDP come from in the first place?" Very few countries exist purely by extracting raw materials. Most wealth instead comes from trade and commerce, and this depends on a large and well educated workforce and market.
In other words, it is countries with the largest populations that are potentially the richest. The potential is of course hostage to numerous forces, including geography and history.