Editor's note: This story updated with new seasonallly adjusted annual rate data reflecting changes to seasonal factors released Aug. 2 by the U.S. Bureau of Economic Analysis.

Large trucks remain the primary spark to U.S. light-vehicle sales, as the sector continued to be the fastest-growing major segment in the market in July.

With help from small LVs and most cross/utility vehicle groups, large trucks spurred July’s LV seasonally adjusted annual rate to 15.7 million units.

Although the SAAR fell below June’s 15.8 million, it still is the second highest for the year and marks an improvement from the 15.4 million rate in the year’s first half. The performance also was 10% higher than same-month 2012’s 14.2 million.

Industry LV sales totaled 1.31 million in July, equaling 52,373 units over each of the month’s 25 selling days. That’s 9.3% above like-2012’s 47,921-unit daily pace over 24 days.

Based on data released by Ford and General Motors, industry results appear to have been hurt somewhat by a temporary drop in fleet deliveries. But both manufacturers expect orders to resume their normal pace during the rest of the year.

Sales of large light trucks, which include pickups, SUVs, CUVs, and vans, plus their luxury versions, increased 18.8% over year-ago and are up 19.6% through July. The light-truck segment could be headed for a 6-year high in market share in 2013. Year-to-date penetration of 18.8% is well above year-ago’s 17.0% and could push 20% by the end of 2013.

Large pickups, which account for more than half of large-truck volume, continued to soar thanks to the segment’s three main players, Chrysler, Ford and GM.

In total, large-pickup deliveries increased 23.2% in July from year-ago and are up 22.2% for the first seven months. Of the high-volume segments, large pickups by far have posted the most growth year-to-date, followed by Upper Middle cars (17.0%), Middle Cross/Utility Vehicles (11.4%) and Upper Small Cars (8.7%).

GM large-pickup sales surged 37.7% above like-2012 and are up 25.6% year-to-date. The auto maker says about 15% of combined Chevrolet Silverado and GMC Sierra July deliveries were redesigned versions that started production earlier this year.

Large-pickup sales at Ford rose 16.8% and Chrysler’s Ram pickup deliveries increased 23.5%.

The segment accounted for 12.0% of July’s LV sales, compared with year-ago’s 10.7%. Year-to-date share stands at 11.7% vs. like-2012’s 10.4%.

Large-pickup volume will continue to grow as the industry heads into what is typically a seasonally strong period.

Furthermore, new product from GM will goose segment sales further as ’14 models become more readily available. Aggressive production schedules early in the year have given the auto maker solid Silverado/Sierra inventory heading into the final five months of 2013, despite having to temporarily slow output at two plants during the changeover to newer versions.

Other areas of strength included small cars and CUVs, which combined for a 17.0% uptick from year-ago, and Upper Middle Cars, up 24.7%. All segment groups except SUVs and Vans increased from year-ago.

Small and Middle Luxury SUVs brought down the SUV Group, while the Small and Large Van segments both recorded declines.

Other weakness could be seen in Lower Middle Cars and Upper and Specialty Luxury cars, although declines in those segments didn’t stop the Middle and Luxury Car groups from recording gains.

All auto makers except Kia, Volvo and Volkswagen/Audi posted increases in July over year-ago.

Among the majors, Honda saw the largest jump (16.1%), followed by Toyota (12.6%) and GM (11.7%).

Other big gainers included Mercedes, Jaguar/Land Rover, Mazda, Mitsubishi, Porsche and Subaru.

hstoddard@wardsauto.coms