How to read the Stock CPU Usage data
Solution 1:
This should be the Unix load average. Wikipedia has a nice article about this.
The numbers show the average load of the CPU in different time intervals. From left to right: last minute/last five minutes/last fifteen minutes
Solution 2:
So far this has been the most helpful source of information regarding this I could find. Apparently the numbers do NOT reperesent load average in %: http://forum.xda-developers.com/showthread.php?t=1495763