North Dakota is ending the decade with its highest population since 2000, according to Census Bureau figures released Wednesday.
The state's population grew by 5,423 people from July 2008 to July 2009, keeping it the 48th most populous state, the Census Bureau said.
The bureau's most recent estimate put North Dakota's population at 646,844 in July 2009, up from 641,421 in 2008. It was the first time this decade that the state's population surpassed the 2000 count of 642,200.
The population increase made North Dakota the 23rd fastest-growing state in the nation, percentage-wise, according to the bureau. It ranks 45th in overall growth.
North Dakota's population is up more than 14,000 people from a decade-low of 632,809 in 2003.
"The biggest factor right now is the strong economy and the jobs," said Rod Backman, chairman of the North Dakota Census Committee, a group consisting of representatives from several state agencies.
North Dakota's booming oil patch in the western part of the state has helped push the population, he said.
"Oil is definitely part of it, but the growth is spread across the whole state," he said.
Only Vermont and Wyoming have fewer residents than North Dakota. Alaska's population surpassed North Dakota's population this decade.
North Dakota's population peaked at 680,845 in 1930, according to Richard Rathge, the state Data Center director and North Dakota demographer.
Rathge said since 2005, the state has shown a "sustained upward trend due largely to our robust economy."
The census estimates show North Dakota had 9,052 births compared with 5,632 deaths from July 2008 to July 2009. Backman said the number of births during that year was the highest this decade.
North Dakota gained 1,375 residents from other states from July 2008 to July 2009, and 521 residents from other countries. Backman said it was only the second time this decade that North Dakota gained more residents from other states than it lost.
"The big story here is domestic in-migration," Backman said. "We're finally on the plus side. We've been dealing with minus numbers virtually the whole decade."
North Dakota lost 381 residents to other states from July 2007 to July 2008, but gained 503 residents from other countries, the Census Bureau said.