Which countries rank among the top five in terms of population worldwide?

The largest countries in the world in terms of population are China and India, with both countries now having populations of well over a billion. The United States comes in third with just under 325 million residents. Indonesia and Pakistan are fourth and fifth respectively. The BRIC countries (Brazil, Russia, India and China), generally regarded as the four major emerging economies expected to dominate in the 21st century, are all in the top ten most populous countries, indicating how important the sheer size of their populations are to their economic expansion.