The authors state, "After 30 years of making incremental changes (in grading), the amount of rise has become so large that what's happening becomes clear: mediocre students are getting higher and higher grades." In their database of over 400 colleges and universities covering the whole range of our higher education system, from large and prestigious universities to small, non-selective colleges, the researchers found not one where grades had remained level over the last 50 years. The overall rise in grades nationally has brought about a tripling of the percentage of A grades, although some schools have been much more "generous" than others.