Students taking BPL5100 are asking about ratios for both individual companies and industries. There is a subject guide on Ratio Analysis and Rasun has just updated all the links so you can point students there.
If students need industry ratios the two best sources are the RMA Annual Statement Studies and Dun and Bradstreet's Industry Norms and Key Business Ratios (both in the reference collection). Students will need to know the industry NAICS codes to use RMA and the SIC code for D&B.
Factiva and Mergent Online are good sources for company ratios. EDGAR Online I-Metrix probably has the most complete list as they provide ratios computed on an annual, quarterly, and trailing 12 month basis. Their data goes back ten years and can be exported to excel. To find the data, choose a company first, then click on "Ratios" under "Financials" in the left column.