1) Based on teachers I know and have discussed this with (yes, yes, not a valid sample, blah blah blah...) I can't imagine that the 99% stat quoted is anywhere near accurate. Many teachers have problems with posting student data, especially in elementary school where I teach.
2) I can't think of one instance during my career where comparing "achievement levels" or anything like them have motivated the lower performing kids, the ones that the NCLP, RTTT, and other government programs say we are supposed to be helping by "analyzing and sharing data with kids". What I have seen happen over and over is jealousy and hatred formed for higher kids in the class, and the lowering of self-image and tendency to give up for the lower kids (not the ones scoring poorly because they are not really trying, but the ones who truly need help).
This practice is certainly the rage among administrators who don't actually have to deal with kids though.