The Chinese Population 1990-2050 (Nada and Rizna)

1990: 1.1352 billion (21.6% of the world)
 2000: 1.2626 billion (20.9% of the world)
 2010: 1.34 billion
 2050: 1.3 billion

WHY: The Chinese population decreases because there’s a policy forcing parents to only have a single child.    

Sources :
1. http://www.oecd.org/newsroom/34992235.pdf
2. http://geography.about.com/od/populationgeography/a/chinapopulation.htm
 3. http://www.reuters.com/article/2011/04/28/us-china-census-idUSTRE73R0DA20110428
 4. http://www.firstpost.com/india/india-to-overtake-chinas-population-by-2050-says-study-1147487.html