It depends on the school. The more a school inflates the grades, or the ease of courses, the higher the GPAs have to be. There would be no sense in having an honors designation if 90% of the people received it.
It has nothing to do with grade inflation, it has to do with standards. People bitch so much about grade inflation but they don't realize at the top institutions that most of the people there would be valedictorians at the pleb schools.