I've just come up with some estimates of this, based on samples from the first five months in 2007, and searches in MEGA;MEGA on Lexis. The estimates are only estimates, for a variety of reasons, but I think they're good ballpark judgments.
So my riddles to you:
(1) How many times per month do U.S. courts — in Lexis-accessible opinions — cite student-written law review articles (denominated Note, Comment, Case Note, and Casenote, though excluding faculty-written works denominated Comment)?
(2) How many times per month do U.S. courts cite non-student-written law review articles?
Let's see who can get closest to right, or at least closest to my estimates of what's right. (By the way, there are a total of about 25,000 Lexis-accessible cases put out per month.) [UPDATE: I should also note that there seem to be about 2500 student articles published per year, and about 9000 non-student articles.]