Secondary sources:
We have a couple online sourced that provide ratios, but they are limited in the number of companies they follow and/or the type of ratios they provide. However, if you are in those databases already, it may be simple to pull the ratios directly from them.
When you do an industry search, and display the results, ratios are listed under the tab to the far right, "Key Statistics." Please provide feedback on whether this database was useful to you or not..
These books provide background on understanding and using ratio analysis.
The full list of books about ratio analysis and financial statements. Below are the "classics" and highlighted materials:
Financial Statement Analysis, 5th ed. by 
Financial Ratios by 
Business Ratios and Formulas, 3rd ed. by 
Key Management Ratios: the 100+ ratios every manager needs to know, 4th rev. ed. by 
Total Management by Ratios: an analytic approach to management control and stock market valuations by 
Handbook of Business and Financial Ratios by 
Understanding and Analyzing Financial Statements by
Perfect for any accounting course where analyzing financial statements and understanding financial ratios is important.
