Source: CIA World Factbook
Editor's note: In our Comparisons series, we examine statistics or world rankings to show how different countries and territories stack up with one another.
(CNN) -- The world's population is about to reach 7 billion on Monday, according to the United Nations.
More than a third of the globe's people are in two countries.
China and India account for more than 1 billion people each. Both have at least three times as many people as the United States, which has the world's third-largest population at a little more than 300 million.
Indonesia and Brazil round out the top five, according to the most recent estimates from the CIA World Factbook.
Twelve countries in the world have more than 100 million people. Eight of them are Asian countries. The other four are the U.S., Brazil, Nigeria and Mexico.
At the bottom of the list is Pitcairn Islands, with an estimated 48 people. The British territory is in the south Pacific.
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