When the US joined World War I in April, 1917 it began purchasing trucks in larger numbers.
"Total built" usually includes for US forces and any export orders.
In 1939–1941, the US Army Quartermaster Corps was developing a full, and largely standardized line of tactical trucks, that could all operate off-road, and in all weather.
In 1941, trucks of 1⁄4-ton, 1⁄2-ton, 1+1⁄2-ton, and 3-ton load capacity, (4x4), and of 2+1⁄2-ton, 4-ton, and 7+1⁄2-tons, (6x6), were in production, and several other types had been added.
These trucks were designated by chassis type, followed by their manufacturer and model.