WASHINGTON – Job openings dropped in May from the previous month and layoffs edged up, new evidence that employers are reluctant to add workers.

The decline in job openings comes after a sharp rise the previous two months, driven by temporary government hiring for the 2010 census and more openings in the private sector. As a result, the number of available jobs has rebounded since the depths of the recession but remains well below pre-recession levels.

The Labor Department said Tuesday that job openings fell to 3.2 million in May from 3.3 million in the previous month. April’s upwardly revised figure was the highest in 18 months.

The report, known as the Job Openings and Labor Turnover survey, reveals a competitive job market. There were about 4.7 unemployed people, on average, for each job opening in May. That’s down from the peak of 6.3 last November, but is much higher than the 1.8 per opening when the recession began in December 2007.

May’s job openings are 37 percent above the low point of 2.3 million openings in July 2009. But the figure is still far below pre-recession levels of about 4.5 million.

And the improvement in some industries is slowing. Manufacturing, for example, saw openings rise by only 1,000 in May to 196,000. That compares to average gains of 14,000 in the previous three months.