China had the largest population in 2005. In fact, until 2023, China had been the most populous country since the United Nations began keeping records in 1950. In 2005, China's population was 1.31 billion. India was the second most populous country in 2005, at about 1.1 billion. The total global population in 2005 was approximately 6,464,750,000, meaning that China and India together accounted for more than one-third of the world's population.
The country with the third-largest population in 2005 was the United States, which had just about 295 million people. Indonesia was number 4, with a population of about 240 million people. Brazil, with 186 million people, rounded out the top five in 2005.
India surpassed China in population in 2023. In 2023, India's population is 1,428,627,663, while China's is 1,425,671,352. The United States is still the third most populous country in the world, with a population of 339,996,563. Indonesia is still fourth, at 277,534,122. In 2023, Pakistan has moved into the top five, with a population of 240,485,658.
Population is a function of several factors, including mortality and fertility rates. Estimates are that India's population will continue to grow faster than China's through 2050. Projections are that the United States, Indonesia, and Pakistan will still be No. 3, 4, and 5, respectively in 2050.