People get hurt on the Mountain from time to time. In my original Mount Whitney Book they gave examples. Broken Bones, scrapes, bruises Hypothermia etc. Some have been hurt from rockfall set loose by other climbers...like up above Iceberg lake.
On the Mountaineers Route, rock climbers have been hurt and killed, although not that often considering how skillfull they are.
Up above the Notch, a few people have slid off and died walking across the sometimes frozen Easy Traverse.
A few years ago someone feel off the Ebersbacher ledges. Consequently the Forest Service moved the trail further away from the edge.
As far as risk goes, you are much more likely to be hurt or killed driving to and from the mountain.
Overall though, if you are cautious and carefull, and observant, these need not happen to you. I have been up and down the Mountaineers route with many others on many trips. All these people had various levels of hiking experience. Most were not climbers.
I think the average rate of fatalities is very small but the mountain deserves respect. Just use common sense and you should be fine.