<P> The first half of the 20th century in Imperial Russia and the Soviet Union was marked by a succession of major wars, famines and other disasters which caused large - scale population losses (approximately 60 million excess deaths). After the collapse of the Soviet Union, Russia's population declined significantly--from 150 million in 1991 to 143 million in 2012--but by 2013 this decline appeared to have halted . </P> <P> Many countries in the developing world have experienced extremely rapid population growth since the early 20th century, due to economic development and improvements in public health . China's population rose from approximately 430 million in 1850 to 580 million in 1953, and now stands at over 1.3 billion . The population of the Indian subcontinent, which was about 125 million in 1750, increased to 389 million in 1941; today, India, Pakistan and Bangladesh are collectively home to about 1.63 billion people . Java had about 5 million inhabitants in 1815; its present - day successor, Indonesia, now has a population of over 140 million . In just one hundred years, the population of Brazil decoupled (x10), from about 17 million in 1900, or about 1% of the world population in that year, to about 176 million in 2000, or almost 3% of the global population in the very early 21st century . Mexico's population grew from 13.6 million in 1900 to about 112 million in 2010 . Between the 1920s and 2000s, Kenya's population grew from 2.9 million to 37 million . </P> <Table> <Tr> <Th_colspan="10"> World population milestones in billions </Th> </Tr> <Tr> <Th> Population </Th> <Th> </Th> <Th> </Th> <Th> </Th> <Th> </Th> <Th> 5 </Th> <Th> 6 </Th> <Th> 7 </Th> <Th> 8 </Th> <Th> 9 </Th> </Tr> <Tr> <Th> Year </Th> <Td> 1804 </Td> <Td> 1927 </Td> <Td> 1960 </Td> <Td> </Td> <Td> </Td> <Td> 1999 </Td> <Td> 2011 </Td> <Td> 2024 </Td> <Td> 2042 </Td> </Tr> <Tr> <Th> Years elapsed </Th> <Td>---- </Td> <Td> 123 </Td> <Td> 33 </Td> <Td> 14 </Td> <Td> 13 </Td> <Td> 12 </Td> <Td> 12 </Td> <Td> 13 </Td> <Td> 18 </Td> </Tr> </Table> <Tr> <Th_colspan="10"> World population milestones in billions </Th> </Tr>

When did the world population reach 2 billion