I'm using Top from the procps-ng package, version 3.3.12. The man page leaves out what the I state stands for
28. S -- Process Status The status of the task which can be one of: D = uninterruptible sleep R = running S = sleeping T = stopped by job control signal t = stopped by debugger during trace Z = zombie I see many processes started by root in this state, what does it mean?
top's documentation has has been reported as a bug and fixed in procps version 3.3.13.