The growth momentum of the heavy-duty truck sector has been declining since 2010 when China surpassed the million-vehicle mark in terms of heavy-duty truck sales.

FORBES: Making Sense Of China's Numbers

Unlike the light-duty vehicle market, most medium- and heavy-duty truck purchasers operate on slim profit margins where fuel costs are a major factor in their economic survival.

FORBES: Magazine Article

In addition to medium and heavy-duty trucks and buses which are clearly used by businesses, commercial vehicle numbers in China include sales of light trucks and mini trucks and buses, many of which are used by individuals and small businesses.

FORBES: China's key economic indicator: auto sales