Revenue growth among the 22 publicly traded staffing firms that operate in North America improved for the fourth consecutive quarter in the fourth quarter of last year, according to a new report released by Staffing Industry Analysts just ahead of the first quarter's earnings-release season.

Quarterly revenue growth accelerated to a median 8.5% year over year in the fourth quarter from a median of year over year 5.9% in the third quarter of 2017.

Median revenue growth still rose when adjusted for acquisitions, currency exchange, divestitures and, in some cases, differences in billing days. Here, median revenue growth accelerated to 5.6% year over year in the fourth quarter from 2.6% in the third quarter year over year.

“There is an outperformance in total revenue growth among some of the larger staffing firms due to higher growth rates in certain European markets,” according to the report by Brian Wallins, senior research analyst at Staffing Industry Analysts. “For example, the average adjusted revenue growth rate among the five companies with more than $1 billion of revenue in 4Q17 was 6.8% — Adecco, Randstad, ManpowerGroup (NYSE: MAN), Kelly Services (NASD: KELYA) and Robert Half (NYSE: RHI) — compared to 1.7% for the remaining firms.”

The report comes as publicly traded staffing firms are slated to begin reporting first-quarter earnings. ManpowerGroup is set to report results this week as it CTG (NASD: CTG)

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