The rest of gradeinflation.com gives much more information you may find interesting.
The reason for this is that the more students they fail, the better they look.
This is also incorrect. Far more important in the school's rankings are (a) the percent of their admitted class to accept the admissions offer, and (b) a higher number of students who get job offers after graduating. This incentivizes schools to lower failure rates (US News and World Report reports graduation rates and rolls them into rankings because they know it turns off most prospective students), and also to increase grades to make their students' resumes look better.