美國 美国人口达到3亿。[http:--www.census.gov-Press-Release-www-releases-archives-population-007616.html 美国人口普查局]url=http:--www.census.gov-Press-Release-www-releases-archives-population-007616.html [http:--news.xinhuanet.com-world-2006-10-18-content_5216895.htm 新华网] url=https:--archive.today-20130428152755-http:--news.xinhuanet.com-world-2006-10-18-content_5216895.htm