DAYTON — Ohio employers posted more than 18,000 new online help-wanted ads last month as demand for labor continued to strengthen across the state, although unemployment remained stubbornly high.

The surge in online vacancies in Ohio represented more than 16 percent of the Midwest’s total increase of 112,900 new listings, according to the monthly survey from The Conference Board.

Illinois, which saw listings climb by 23,400 to 175,400, was the only Midwestern state to top Ohio, which had about 148,000 online openings last month.

Nationwide, online labor demand grew in 49 states, led by California (up 56,800); Texas (up 31,900); New York (up 29,400); Illinois and Florida (up 20,200).

All told, online vacancies rose by 438,000 to 4.3 million last month.

“The very strong seasonal gain to start 2011 is welcome news following seven months of essentially flat U.S. labor demand,” said June Shelp, vice president at The Conference Board. “Last year, after a promising start, labor demand fizzled, and the last half of 2010 was actually flat with no appreciable gains in job demand.’’

The increase in online labor demand underscores the findings of several recent surveys in which employers said they planned to add workers this year because they were seeing a pickup in their businesses.

But those employers would have to create a tremendous number of jobs to make a dent in Ohio’s unemployment rate of 9.6 percent.

Presently, there are 10.6 million more unemployed workers than online job openings, The Conference Board reported.

Contact this reporter at (937) 225-2437 or rtucker@DaytonDailyNews.com.