Mongolia's total population as of January 2015 was estimated by the U.S. Census Bureau to be 3,000,251 people, ranking around 121st in the world. But the U.S. Department of State Bureau of East Asian and Pacific Affairs uses the United Nations (UN) estimations instead of the U.S. Census Bureau estimations. United Nations Department of Economic and Social Affairs Population Division estimates Mongolia's total population (mid-2007) as 2,629,000 (11% less than the U.S. Census Bureau figure). UN estimates resemble those made by the Mongolian National Statistical Office (2,612,900, end of June 2007). Mongolia's population growth rate is estimated at 1.2% (2007 est.). About 59% of the total population is under age 30, 27% of whom are under 14. This relatively young and growing population has placed strains on Mongolia's economy.