Between 2008 and 2009 the population of Porter County grew but at a much slower rate than the 10-year annual average.

In its analysis of the 2009 population estimates recently released by the U.S. Census Bureau, the Indiana Business Research Center (IBRC) at Indiana University is attributing that sluggishness in migration—observable in counties throughout the state—to the recession.

“The economic slump of 2008 and 2009 appears to have dampened population movement in many parts of Indiana,” the IBRC said in a statement released last week.

Over the last 10 years, the population of Porter County increased by an estimated 16,800 or 11.4 percent—to 163,598 on July 1, 2009—for an annual average of 1,680. But between July 1, 2008, and July the population of Porter County increased by only 1,298 or 0.8 percent.

Porter County did maintain its rank as the ninth most populous county in Indiana.

Lake County, meanwhile, experienced an even smaller population increase. Between 2008 and 2009 the population of Lake County—still the second most populous county in the state with 494,211 residents—increased by only an estimated 768 or 0.2 percent, compared to its 10-year annual increase of 965.

On the other hand, over the same one-year period the population of LaPorte County—the 15th most populous county in the state with 111,063 residents—increased by an estimated 309 or 0.3 percent, not a lot in raw numbers but nevertheless the single greatest spike over the last 10 years, which saw the county grow by a total of 957 or only 96 residents per year.

Six Indiana counties have populations over 200,000, the IBRC noted: Marion with 890,880, making it the nation’s 56th largest county; then Lake (494,211); Allen (353,890); Hamilton (279,290); St. Joseph (267,610); and Elkhart (200,500). Each has grown over the last decade: Marion by 3.5 percent, for example, and Lake by 2 percent. But Hamilton, the fast-growing county in the state, exploded over those 10 years with a 53-percent increase in population.

Even so, the IBRC said, of the 15 counties which led the state in net in-migration between 2000 and 2008, 10 had a net migration in 2009 far below their average for the previous years of the decade. The IBRC is blaming the economy.

“In Central Indiana, many of the suburban counties have seen a decline in migration in 2009 while Marion County registered its first annual net in-migration in this decade as fewer residents moved to surrounding counties,” IBRC analyst Matt Kinghorn said.

In the last decade 40 of Indiana’s 92 counties saw population declines. Benton County led the state with an overall decrease of 9 percent over those 10 years, followed by White, Blackford, and Wabash counties with a 7-percent loss each.