That "help wanted" sign is not your imagination.

U.S. employers posted the most job openings in four years in June, a positive signal that hiring may pick up.

According to the Labor Department, job openings rose to a seasonally adjusted 3.8 million in June, up from 3.7 million in May. That's the highest  number of openings since May 2008.  Adding to the good news, layoffs fell during the same period.

The data follow Friday's report that said employers in July added the most jobs in five months. A rise in openings could signal better hiring in the coming months. Typically, it takes one to three months to fill a job.

Even with the increase in job openings, hiring is competitive. There were 12.7 million unemployed people in June.  That translates, on average, to 3.4 unemployed people for each job.  In a healthy job market, the ratio is usually around 2 to 1.