North Dakota's population grew to 635,867 in 2006, a slight increase of 0.2 percent from 634,605 in 2005.

This month's ""Population Bulletin,"" a monthly publication from the North Dakota State Data Center at North Dakota State University, focuses on county population estimates released by the U.S. Census Bureau's Population Division. The 2005 estimate of 634,605 differs from the 2005 estimate released one year ago.

Keep in mind that most administrative record data sources used in calculating population estimates lag the current estimate year by up to two years. As updated data become available, the past year's estimates are revised so that the current year is always based on the most recent data available.

""This lag effect can be the source of confusion and frustration for those monitoring population changes,"" says Richard Rathge, State Data Center director. ""However, it is important that we use the most accurate and updated data, especially in trend lines. Thus, we need to deal with systematic corrections."

In North Dakota, the population grew in 15 counties from 2005 to 2006. Sioux and Burleigh counties had the largest percentage growth (2.1 percent and 2 percent, respectively) followed by Cass and McKenzie counties (1.6 percent each). Cavalier County showed the largest percentage decline during this period (4.1 percent), followed by Towner County (3.8 percent).

The population in North Dakota also continues to be centralized. The majority of people living in North Dakota (55.7 percent) reside in the top five populated counties (Cass, Burleigh, Grand Forks, Ward and Morton). This proportion is up from 53.4 percent in 2000.

Among all the states in 2006, North Dakota ranked 48th in total population and had the ninth lowest population growth rate from 2005 to 2006. Three states lost population during this time. Louisiana declined 4.9 percent, Rhode Island 0.6 percent and Michigan 0.1 percent. The fastest growing states were Nevada (3.5 percent) and Arizona (3.5 percent).

NDSU Agriculture Communication