PITTSFIELD — Berkshire County's population has been declining since 1970, but the region is currently losing more people at a higher rate than any other area of Massachusetts, according to U.S. Census Bureau figures.
A total of 737 people left the Berkshires in the 12 months ending on July 1, 2015, a drop of 0.6 percent, according to population estimates that were released Thursday by the Census Bureau.
Both those figures are higher than in any of the state's 13 other counties over that same time span.
"You always need to keep in mind that these are estimates," said Berkshire Regional Planning Commission Executive Director Nathaniel W. Karns, who has not seen the most recent figures. "They're based on a survey, not the decennial census.
"But it wouldn't surprise me," Karns said, referring to the 0.6 percent drop in the county's population. "We have an aging population, and we have fewer kids. I think that's understood by most people who are paying attention to what's going on in the region."
Berkshire County has one of the oldest populations in the state, with higher percentages of people over age 65 and between the ages of 75 and 84 than the rest of Massachusetts. During the 12-month period that ended last July, 502 more deaths than births were reported in Berkshire County, according to the Census Bureau figures.
Berkshire County's total population is now 127,333, a decline of 3,400 residents since the 2010 decennial census. In Massachusetts, only Dukes, Franklin and Nantucket counties have fewer people.
Franklin County has the second-highest percentage of population decline (0.5 percent) during the 12 months that ended in July, but Barnstable County has lost the second most residents (332).
On the plus side, Suffolk County, which includes the city of Boston, is the state's fastest-growing county. Suffolk added 8,312 residents during the 12 month period that ended in July, an increase of 1.1 percent.
However, Suffolk is the only county in Massachusetts with a growth rate higher than 1 percent. The state of Massachusetts added 39,298 residents, an increase of 0.6 percent, in the 12 month period that ended in July.
Middlesex is the state's most populated county with 1.6 million residents, including 12,616 who arrived during the period covered by the census figures, an increase of 0.8 percent.
"Statewide we're being pulled along by Boston, which is doing well," Karns said. "The rest of the state is sitting in basically the same place since the Great Recession started. Economic improvements haven't filtered into the rest of the state."
In the rest of Western Massachusetts, Hampden County added 1,124 residents, an increase of 0.2 percent, while Hampshire County added 186 residents, a 0.1 percent jump.
Karns said efforts to try to increase the state's population base have been slow to take hold.
"The efforts that are going on to try to reverse that (decline) are just really in their beginning stages," he said. "When you have a big ship it takes awhile to get the thing turning in a different direction. This is one of those big ship issues."
Contact Tony Dobrowolski at 413-496-6224.