That seems consistent w/the "95% of what we teach" number. As Douglas Adams wrote, a computer "...was, on the other hand, very good at being a slow and dim-witted pupil. ... And the more slow, and dim-witted the pupil, the more you have to break things down into more and more simple ideas. And that's really the essence of programming."
link: http://www.oopsla.org/2005/ShowEvent.do?id=403
this google video is also cool: http://video.google.com/videoplay?docid=-2726904509434151616&q=gerald+sussman
anyone have any sussman stories they'll like to share?