Wages in China

Sometimes when I go to restaurants and cafes frequented by expats I wonder about the logistics of running such a business, and how much they pay for labor and for rent. Well, after looking in the employment ads on www.thatsbj.com, I know. Here's what a pizza place (best in Beijing in my opinion) which is opening a new branch is offering:
(spelling errors are not mine)

8 Waiters/waitness(basic English required)
--1200/m-1500/m, depend on experience

2 Cooks(know how to cook Pizza)
--2000 first month, 2500 second, 3000 after probation.

2 small cook(knowledagble with salad and appetizer)
--1500/m first month, 2000 after probation.

2 dishwashers(age over 35)--800/m
1 cashier--1500/m

volunteer-- you will get free food and beer if you want help us out in the rush hours.

I was struck by how little these people are earning (our apartment costs 3100 per month, and our food budget is about 1000 per week, and we are at least somewhat frugal), but also by how well they compare to college grads salaries. A good job for a recent grad pays about 4000 per month, but I also know a girl making 2300, and another friend did an internship where she got 20 per day, although she probably did it mostly for the experience.

It's also notable how big the discrepancy is between the dishwashers and the pizza cooks - nearly four fold! Granted, knowing how to make decent pizza is a fairly rare skill in China, but I can't imagine it's that hard to teach. . .

In contrast, I make 150 RMB per hour of teaching at one job, and 200 for an hour and a half an another.