AVERAGE SALARY FOR PRODUCTION POSITIONS?

I’m researching the production department of consumer magazines..

Would anybody be able to tell me what a typical salary may be for a:
production assistant?
Prod. Manager?
Prod. Director?

Does the salary depend on publication?

Is there an average for production positions at:

Conde Nast?
Hearst?
Rodale?

Thank you so much for your time!