A job fair in May in San Francisco (Justin Sullivan/Getty Images)

Hiring is on the uptick in at least area of the U.S. economy: temporary work, the Associated Press reports. Part-time workers are being hired at some of the nation's largest corporations. Combined, they account for nearly 17 million people, who have only tenuous ties to the companies that pay them.

From Wal-Mart to General Motors to PepsiCo, companies are increasingly turning to temps and to a much larger universe of freelancers, contract workers and consultants. Combined, these workers number nearly 17 million people who have only tenuous ties to the companies that pay them โ€” about 12 percent of everyone with a job.

Hiring is always healthy for an economy. Yet the rise in temp and contract work shows that many employers aren't willing to hire for the long run.

The number of temps has jumped more than 50 percent since the recession ended four years ago to nearly 2.7 million โ€” the most on government records dating to 1990. In no other sector has hiring come close.

Driving the trend are lingering uncertainty about the economy and employers' desire for more flexibility in matching their payrolls to their revenue. Some employers have also sought to sidestep the new health care law's rule that they provide medical coverage for permanent workers. Last week, though, the Obama administration delayed that provision of the law for a year.

The use of temps has extended into sectors that seldom used them in the past โ€” professional services, for example, which include lawyers, doctors and information technology specialists.

Read more at the Associated Press.