The Trucker reported heavy-duty new truck sales have recorded the best August in six years, another in a string of comparatively good reports — even as the numbers shows signs of a plateau in the industry recovery.

According to figures provided to The Trucker by Ward’s Automotive, Class 8 sales totaled 16,497 trucks in the United States, up 9.4% from August 2011.

The year-over-year improvement was the 32nd consecutive, although the rate of improvement has slowed. This total is 127% higher than the sales for the same period in 2009, the worst year in a generation.

The report notes Daimler Trucks North America’s Freightliner led the field,with a 9.4% gain over July and a 31.2% improvement from the year before making August Freightliner’s best month since January 2007. Navistar sold 3,039 International brand trucks in August, a 6.8 % decline from July and a 10.9% decrease from the same month in 2011. Peterbilt was down 11.8% from July and down 10.8 % from August 2011, while Kenworth was up 2.8% from July and up 1.7% from August 2011. Volvo Group’s Mack Trucks was down 11.3% from July but up 56.6% from the year before.

The report notes month-to-month numbers can vary greatly — especially between quarters or from year’s end — depending on an OEM’s sales incentives and reporting procedures, or more recently, supplier shortages and production line issues.