About three posts down at the link. Looks like they sent this out by e-mail to admitted students. It looks like it is more thorough than what they reported to US News (based on the spreadsheet on your site). They have salary data on 95% of the class, and report a total class median salary of ~96,000, which seems very accurate for a school like Illinois.
HAHAHAHAHAHA. The data are a flaming crock of shit.
The most recent NLJ report shows the class of 2009 has 26.7% of their grads in NLJ 250 firms. Whatever else you say about it, the NLJ data is pretty rock solid and dependable. They're an enormous resource.
Source: http://www.law.com/jsp/nlj/PubArticleNL ... hbxlogin=1
The NLJ 250 is a list of just the biggest firms in the country, nothing else. I believe the smallest firm listed has just under 200 attorneys.
So, we can safely assume that a firm of >= 250 attorneys will be an NLJ 250 firm.
Take Illinois' "data" in the absolute most favorable light:
90% of the class employed at graduation * 66% in private practice * 71% listed in firms of 250 or greater = 42.2% at an NLJ 250 firm = B.S.
A huge, steaming, festering pile of bull fucking shit.