MINNEAPOLIS — Population growth in the once-booming Twin Cities suburban counties is slowing down, according to U.S. Census estimates released Thursday.

Growth in the five suburban counties collectively trails Hennepin and Ramsey counties so far this decade, the Star Tribune reported. Since the 1940s, those five counties have always gown at least twice as fast as the two big urban counties — home to Minneapolis and St. Paul — that they border.

But now, Ramsey County, where St. Paul is located, is growing as quickly as suburban neighbor Washington County. For half a century, Ramsey was the slowest-growing of the metro counties. In the 1990s, Washington grew eight times faster.

Anoka and Dakota counties have shown the weakest growth so far in the seven-county metro region.

Consulting demographer Tom Gillaspy said the numbers suggest that the softening of suburban growth, which began around 2005, is “not a short-run thing.”