According to data tracking by the American Trucking Associations (ATA), the turnover rate for drivers at U.S. TL fleets increased slightly in the first quarter this year while remaining at what the group called “historically low levels.”

In the first three months of the year, the trade group said the annualized turnover rate at large TL fleets – those with annual revenues greater than $30 million – rose three percentage points to 74%.

Despite the increase, it remains at near-historic lows and is 15 points lower compared to the same time period in 2016, noted Bob Costello, ATA’s chief economist, in a statement.

“The slight uptick in turnover, despite weak freight volumes in the first quarter, may be indicative of a tightening in the driver market,” he said. “The situation bears watching because if the freight economy picks up significantly, turnover will surely accelerate – as will concerns about the driver shortage.”

ATA added that the turnover rate at small TL fleets increased two percentage points to 66% during the first quarter – 22 points lower than at this time in 2016 – while the turnover rate at LTL carriers, typically very low, also increased just two points to just 10%.

This story originally appeared at Fleet Owner