Long Island’s unemployment rate dipped to 4.0 percent in November, down 0.1 percentage point from a year earlier, state Labor Department data released Tuesday show.

The year-over-year dip in the jobless rate comes amid a recent gain in employment, and a stable or slightly declining number of residents actively looking for work. People are counted as unemployed only if they are actively looking for jobs.

“The number of people who are looking for work has been flat or slightly down,” said James Brown, labor-market analyst in the department’s Brooklyn office. The number of Islanders in the labor force, which counts people working or looking for work, declined by 3,900 from a year earlier to 1.47 million.

“When you combine that with moderate job growth, the result has been that the unemployment rate continues to go lower,” he said.

The unemployment rate is based on a Census sample survey of Island residents no matter where they work.

The unemployment rate in Nassau County fell 0.1 percentage point from last year to 3.7 percent. Unemployment in Suffolk decreased 0.2 percentage point to 4.1 percent.

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The state’s jobless rate for November was 4.7 percent, in line with the nation’s.

The department uses year-over-year comparisons because local data aren’t adjusted for seasonal variables in employment, such as holiday retail hiring.

The Island had 58,000 unemployed residents last month, down 1,700 from the same time last year. The number of employed residents totaled 1.41 million in November, unchanged from a year earlier.

The recent unemployment rate was the lowest for November since 2007, John A. Rizzo, chief economist for the Long Island Association, said in an email.

“The labor force and numbers of persons employed were nearly the same as for last year, however, and the unemployment rate was only slightly lower,” Rizzo added. “This suggests that Long Island’s labor market is approaching full employment, which should put upward pressure on wages in the coming year.”

In a full-employment economy, it is difficult to reduce the unemployment rate any lower.

Freeport Village had the highest unemployment rate among the Island’s incorporated areas: 4.7 percent. Glen Cove had the lowest jobless rate: 3.4 percent.