Director of US Census Bureau Robert Groves speaks at a presentation of the 2010 Census US population in Washington D.C., capital of the Untied States, Dec. 21, 2010. The US population grew 9.7 percent over the last decade, the slowest growth since the 1930s, the Census Bureau said on Tuesday. [Xinhua]

(L to R) Director of US Census Bureau Robert Groves, Acting Deputy Commerce Secretary Rebecca Blank and US Commerce Secretary Gary Locke attend a presentation of the 2010 Census US population in Washington D.C., capital of the Untied States, Dec. 21, 2010. The US population grew 9.7 percent over the last decade, the slowest growth since the 1930s, the Census Bureau said on Tuesday. [Xinhua]