Feedback on Writing Programs

I am hoping some of you might be able to help me out with a little fact finding. Specifically, I'm looking for research and personal information regarding the growth of Writing Concentrations, Writing Studies Majors, writing courses, etc. I'm wondering, among other things, what kind of impact writing concentrations are having on the size and nature of English departments on the whole. How has the addition of writing concentration courses impacted enrollment in the department overall? How has it shifted the relationship between Writing and Lit, if at all? Do you know of any research studies or other resources that roughly address the questions above?