Nevada was No. 1 among states for the 18th consecutive year with a growth rate of 4.1 percent, according to federal population estimates released Dec. 22.
Other states gaining in population included Arizona, Florida, Idaho, Georgia, Texas, Utah, Delaware, North Carolina and New Mexico.
Massachusetts was the only state in the nation with a declining population in 2004 and had the lowest growth rate, -0.1 percent, except for the District of Columbia, -0.7. Slow-growing states included New York, North Dakota, Ohio and West Virginia.
The latest U.S. Census Bureau figures show that as of July 1, Massachusetts' growth rate was well below the national rate of 1 percent. Massachusetts had 3,852 fewer residents this year than last.
John Gaviglio, manager of the Massachusetts State Data Center, said reasons for the state's declining population rate are likely tied to migration to other states. But he said he can't be sure because state budget cuts eliminated the work of a demographer to examine statistics, track migration data and do projections that state agencies use to plan aging and health-related programs.
This year North Carolina and New Mexico replaced California and Hawaii on the list of the top 10 fastest growing states.
To estimate population, the Census Bureau compared each state's births against its deaths and also accounted for those who moved into or out of a state from another country or state.
California remained the most populous state in the nation with 35.9 million people in 2004, followed by Texas (22.5 million) and New York (19.2 million).