Hawaii’s unemployment rate fell to a seasonally adjusted 4.3 percent in August, the lowest level in more than five years, the state Department of Labor and Industrial Relations reported Thursday.

The August rate was down from 4.5 percent in July and marked the lowest jobless rate in Hawaii since July 2008 when it was 4.1 percent.

Nationally, the unemployment rate fell to 7.3 percent in August from 7.4 percent in July.

The state and national unemployment numbers are adjusted for seasonal variations, such as students leaving jobs to return to school after summer break.

County data are not seasonally adjusted. The state reported that the rate in Hono­lulu County fell to 3.8 percent in August from 4.2 percent in July. The rate fell to 5.8 percent from 6.7 percent in Hawaii County, to 4.9 percent from 5.2 percent in Kauai County and to 4.5 percent from 4.8 percent in Maui County.

However, the report was not all positive. The state data showed that while the unemployment rate declined, the overall labor force also shrank, suggesting that some of those searching for a job simply quit looking.

The number of people counted as unemployed — those without jobs but who are actively looking for work — fell by 950 in August, according to the report. But the number of employed grew by only 250.

The result was a decline in the labor force, a phenomenon that also is occurring at the national level and one that some economists have interpreted as a sign that long-term discouraged jobless workers are leaving the workforce. Others have speculated that the drop also may be partly due to some older unemployed workers choosing not to return to the labor force.

Hawaii’s labor force totaled 642,600 in August, down from 643,850 in July and 649,200 in August 2012. The state’s labor force has been shrinking since early 2011 when it peaked at around 660,000.

The unemployment rate is derived largely from a monthly telephone survey of households.

A separate survey of private-sector employers showed that company payrolls grew by a net 400 positions in August from July and by 2,300 from August 2012.

The industry sectors with the biggest job gains in August from July were education and health services, which added 1,500 positions.

There was a gain of 900 jobs in other services, while leisure and hospitality added 600 positions.

The number of state government jobs declined by 2,500, while construction jobs shrank by 1,200, according to the report.