It depends what they are doing and where they are doing. In-house may not pay as much as a design firm for instance. I would recommend taking a look at Salary.com as there are different levels of design.
Production Artist
Graphic Designer
Sr. Graphic Designer
Creative Director
Art Director
A graphic designer makes about $30,600 a year at entry. (United States)
It depends what they are doing and where they are doing. In-house may not pay as much as a design firm for instance. I would recommend taking a look at Salary.com as there are different levels of design.
Production Artist
Graphic Designer
Sr. Graphic Designer
Creative Director
Art Director
etc.