The world of work is changing, and that change is only accelerating with the introduction of the Gig Economy, said Barry Asin, president of Staffing Industry Analysts, during a keynote address today at the Collaboration in the Gig Economy conference in Las Vegas.

Today, there are 44 million Americans engaged in gig/contingent work in the US, and companies spent $792 billion on them in 2015, Asin said.

The majority of that spend, $425.2 billion, went to independent contractors. That was followed by $200 billion for statement-of-work consultants, $115.6 billion for agency temporary workers, $40.1 billion for directly employed temporary workers and $11.5 billion for human cloud workers.

But what is the Gig Economy? All contingent workers are part of the Gig Economy, according to Staffing Industry Analysts’ definition.

“We think that gig is exactly the same thing as contingent work,” Asin said in his keynote address. “The Gig Economy to us is all about work done on a short-term basis.”

The Gig Economy includes traditional staffing, human cloud, independent contractors and more:

The human cloud includes online work services such as Uber and online staffing platforms such as Upwork, along with just-in-time staffing firms such as Shiftgig and freelance management system providers such as Field Nation. The human cloud also includes crowdsourcing firms such as CrowdFlower and Gigwalk. It’s any work with an explicitly defined end date.

Sometimes the terms Gig Economy and Sharing Economy are used interchangeably. However, the sharing economy also includes nonlabor-related online services, the most well-known example being AirBnB. The Gig Economy does not include those services, under SIA’s definition.

More companies also plan to use gig workers. In a survey, large users of staffing services said their ideal share of their workforces that are contingent will be 20% in 10 years from now. That’s up from 15% of their workforce that is contingent today.

A new report on the Gig Economy is now available online from Staffing Industry Analysts.

Asin’s keynote speech got the conference, also known as GigE, rolling. The event in Las Vegas has more than 600 attendees.