The graph is showing how many people are awake. The 93% number reflects the fact that some people were already awake before the quake.

Then according to the graph, 59/85 were awoken from sleep, which is about 71%.

59 awoken = 74 (awake at quake) - 15 (awake before the quake)

85 = 100 - 15 (awake before quake)

Maybe they are adjusting for other things that are not shown on the graph.

Good point. I wonder if they are smoothing the data, which would make the peaks less peaky (which brings up another question, what is the time resolution for UP's ability to measure wakefulness?).

Never mind. The graph is showing areas based on 25 mile radius, and the 93% is for the 15 mile radius.