The states and territories included in the United States Census Bureau's statistics for the United States population, ethnicity, and most other categories include the 50 states and Washington, D.C. Separate statistics are maintained for the five permanently inhabited territories of the United States: Puerto Rico, Guam, the U.S. Virgin Islands, American Samoa, and the Northern Mariana Islands.[1]
As of April 1, 2010, the date of the 2010 United States Census, the nine most populous U.S. states contain slightly more than half of the total population. The 25 least populous states contain less than one-sixth of the total population. California, the most populous state, contains more people than the 21 least populous states combined, and Wyoming, the least populous state, has a population less than any of the 31 most populous U.S. cities.[needs update]