Washington added an estimated 12,100 jobs in November, the largest one-month gain in four years.

The stronger jobs outlook was matched by a substantial plunge in the unemployment rate, from a revised rate of 9.1 percent in October to a preliminary estimate of 8.7 percent in November.

“This is the kind of job growth we need to make a good dent in the unemployment rate,” said Greg Weeks, director of the Employment Security Department’s labor-market information office. He added, “The drop in the unemployment rate was unusually large for November, and I expect it to be revised to a somewhat smaller decline when we get more data.”

In preliminary estimates, nearly every industry sector posted job gains last month.

These included professional and business services, an estimated increase of 4,200 jobs; leisure and hospitality, up 3,800; construction, up 2,000; transportation, warehousing and utilities, up 1,200; manufacturing, up 1,000 (including 1,100 in aerospace); financial activities, up 700; retail trade, up 600; mining and logging, up 200; wholesale trade, up 100; information, up 100.

Jobs were lost in the other-services sector, down 1,300; education & health services, down 400; and government, down 100.

Within the government sector, state agencies lost an estimated 900 jobs, local government added 1,000, and the federal government lost approximately 200 jobs.

Altogether, employment in Washington has increased by an estimated 44,600 since November 2010.

An estimated 303,528 people (seasonally adjusted) in Washington were unemployed and looking for work in October. As of Dec. 10, 67,588 workers in Washington had run out of all unemployment benefits.

Employment Security is a partner in the statewide WorkSource system, which offers a variety of employment and training services for job seekers, including free help with interviewing skills, résumés and job referrals. WorkSource also can help employers recruit and screen for qualified workers, apply for employment tax breaks and qualify for subsidized employee training.

Locations of local WorkSource offices are listed online at www.go2worksource.com and in the blue pages of local telephone books.