What is the undergrad graduation rate for each class from 1937 to 2008?
A knowledgeable archivist isn’t so sure that the University consistently tracked graduation rates. You may need to calculate this yourself from raw numbers. You should first check with the Registrar’s Office to see if they kept that stat on a regular basis. The University Archives has statistics from the Registrar’s Office back to the 1920s, and you could go in and look through the records. See the Inventory of the Office of the University Registrar Records, 1853 – 2000. For instance, the annual statistical reports they used to publish included number of attritions, and would tell how many students withdrew. From the total enrollment, you could subtract the attritions, then figure out a graduation rate. (You should probably consult with a statistician to make sure you’re making a valid calculation.)
There is a web page on on Graduation and retention rates – Undergraduate that starts in the mid-1990s, provided by the Provost’s Office of Institutional Research.