Total CPU Usage = 100 - Idle /* if idle is 66 then CPU Usage is 100 - 66 = 44 */
"mpstat" utility uses the interval from the probe and work out the average CPU usage over that time period.
The mpstat command reports processor statistics in tabular form. Each row of the table represents the activity of one processor. The first table summarizes all activity since boot. Each subsequent table summarizes activity for the preceding interval. All values are rates listed as events per second. CPU usage information is collected for each of the CPUs, then the total is averaged for the Computer Device as a whole.