The answer appears to be: twelve. The man in black, standing leaning to cabin, does not count because he doesn’t wear a straw hat and/or a reflective safety vest. I met this small truck on a county road just north of the Sixth Ring Road in Beijing, driving very fast, as in a great hurry going for an important job. License plate is from Henan Province, which is not very nearby, so this most likely is a flock of immigrant workers.
Crews like this are often deployed to clean the sides of the road, dangerous work with China’s crazy drivers, and very hot in summer and very cold in winter. The workmen usually stay in crappy old farms or in crappy old tents. They earn no more than some 750 yuan a month, or 120 USD. Still, they always seem to be happy, singing and such, and they keep the roads really clean indeed, as plainly visible in this very picture, and these straw hats are actually kinda cool.