Maine’s unemployment rate has reached its lowest point in more than eight years, the state Department of Labor reported Friday.

The preliminary, seasonally adjusted unemployment rate dipped slightly in August to 4.5 percent from 4.6 percent in July, and was down from 5.6 percent in August 2014, the department said. If confirmed, August’s jobless rate would be the lowest in Maine since April 2007, eight months before the Great Recession officially began.

The state’s civilian labor force – those either working or looking for work – was down nearly 2 percent from 713,963 in August 2014 to 700,187 a year later, the department said, while total employment decreased about 0.7 percent from 679,592 to 674,707.

Maine’s workforce has been shrinking since 2013 as an increasing number of baby boomers retire, with not enough young workers entering the labor force to replace them. That trend, which economists have termed the “demographic cliff,” can be seen in declining civilian labor force numbers across the state.

The number of unemployed Mainers actively seeking jobs declined by 8,200 over the 12 months ending in August to 31,100, the Labor Department said. Still, Maine’s employment-to-population ratio estimate of 60.2 percent remained above the U.S. average of 59.4 percent for the 95th consecutive month, it said.

Unemployment rates decreased in all three of Maine’s major metropolitan areas during the 12 months ending in August, but actual employment increased only in the Portland-South Portland-Biddeford metro area.

The Portland area’s unemployment rate, not seasonally adjusted, fell to 3 percent in August from 4 percent a year earlier, according to the Labor Department. The area’s labor force decreased slightly from 204,993 in August 2014 to 204,372 a year later, while total employment increased slightly from 196,715 to 198,340.

“There are a lot of employers looking for qualified workers, and fewer workers looking for jobs, particularly over the last few months,” said Mike Roland, manager of the Portland Career Center.

Roland said hiring for health care workers has been particularly strong, and that there are some labor shortages in that field. Manufacturing and information technology hiring has also been strong, he said, but not as robust as health care.

In the Lewiston-Auburn area, the unemployment rate dropped from 4.9 percent in August 2014 to 3.6 percent a year later. Total employment decreased from 53,517 to 53,176, while the civilian labor force decreased from 56,248 to 55,163.

In the Bangor area, the unemployment rate dropped from 5 percent in August 2014 to 3.8 percent a year later. Total employment decreased from 67,149 to 66,409, while the civilian labor force decreased from 70,657 to 69,010.

The U.S. preliminary unemployment rate of 5.1 percent in August was down slightly from 5.3 percent in July and down from 6.1 percent a year earlier, according to the Labor Department.

The New England unemployment rate averaged 4.6 percent, it said. Rates for other states were 3.6 percent in New Hampshire, 3.6 percent in Vermont, 4.7 percent in Massachusetts, 5.6 percent in Rhode Island, and 5.3 percent in Connecticut.