Some universities survey their graduates to see what they ended up doing shortly after graduation -- employed (and how much they are being paid if employed), still looking for a job, going to graduate school, or "other" (some only show pay of employed graduates). The most useful surveys break down the results by major.
Methodology does differ somewhat, so be careful about making comparisons across universities.
it is also important to realize that most, if not all, of these surveys depends on optional student response. Obviously the students that are currently satisfied with their post-college plans are more likely to respond.