Julie, I didn't mean that the LSAT literally changes its grading scale based on the amount of students. Other factors including, the increased numbers of people taking test, during a recession more professionals going back to school that may do better on the LSAT, etc etc...
I bet you if you were to juxtapose two graphs, one representing attendance and another representing score scale, there would be some interesting extrapolations to make. I hypothesize that you would see the scoring scale easier during non recession years or years when attendance is at normal levels. Those extrapolations would not offer insight as to the reason why by any means.