Staffing Industry Analysts today released its annual list of largest US staffing firms, which included 134 staffing firms with US staffing revenue of more than $100 million in 2015.

The five largest firms in the US are:

1. Allegis Group, $8.63 billion
2. Adecco, $4.627 billion
3. Randstad Holding, $4.625 billion
4. ManpowerGroup Inc. (NYSE: MAN) $3.54 billion
5. Robert Half International Inc. (NYSE: RHI), $3.48 billion

“The companies featured on this year’s report combined to generate $75.7 billion in US staffing revenue last year,” said Timothy Landhuis, research manager at Staffing Industry Analysts. “This marked a solid increase from the $69.4 billion of 2014 revenue featured in last year’s report, and provides evidence of overall growth in staffing revenue among large firms. To cite one example of a segment where growth was apparent, this year’s report contains 20 companies with a healthcare staffing focus that added together generated $7.3 billion.”

Landhuis continued, “In another sign of growth for the US staffing industry last year, this year’s report features 134 companies, up from the 122 firms showcased in last year’s report. While four companies from last year’s report no longer appear due to being acquired (Atterro, Bartech, Creative Circle and The Select Family of Staffing Companies), this decline was offset by the addition of nineteen new staffing companies appearing on this year’s report.”

In this year’s report, revenue estimates reflect “staffing revenue” defined as revenue related to temporary staffing, direct hire, retained search, and temp-to-hire conversion fees.

Corporate members of Staffing Industry Analysts can download the full report.