Thirty percent of U.S. companies intend to increase staffing levels in the second quarter this year, according to a survey of 16,000 employers prepared for release Tuesday.

The report marks the ninth straight quarter that more than 20 percent of the companies surveyed said they plan to add staff. It was 23 percent for the first quarter of this year.

The last time the reading topped 30 percent was in the third quarter of 2005, when 31 percent of companies surveyed said they planned to add staff.

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Six percent of companies surveyed expect to reduce employment in the second quarter, while 58 percent expect no change, the survey said. Six percent of companies were unsure of their plans, according to the survey, which began in 1962.

The trend shows a healthy, stable economy, said Milwaukee-based global staffing firm Manpower Inc.

Manpower CEO Jeff Joerres said a shortage of workers is forcing companies to get out and be more competitive in their hiring practices.

"There is a shortage going on," Joerres said. "Companies are looking for the exact talent they need, and they may be having a more difficult time doing that."

Mining companies expect significant gains in hiring in the second quarter, with 37 percent planning to increase their payrolls and 3 percent planning to decrease, the survey said.

"Demand for coal has skyrocketed in the wake of high oil and gas prices, and mining employers have responded by boosting their hiring plans in recent quarters," Joerres said.

Construction firms outpaced the other industries in the survey, with 43 percent planning to increase staffing and 3 percent planning to reduce it, the survey said.

The hiring outlook in the West outpaced the other regions with 35 percent of companies planning to increase staffing and 5 percent planning to decrease.

The Midwest and the Northeast were the least positive, with each region planning to increase 27 percent. Five percent of Midwest companies surveyed said they planned to decrease staffing compared to 9 percent in the Northeast.

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