Indicates the number of the event. Events are numbered
sequentially from 1 - n. A management station can keep track
of the last event it uploaded and periodically GET-NEXT from
there to determine if there have been any new events. This
means that, as events are removed from the table their indices
are not reused until the next reset to default configuration
(which loses all stored events). Also, the agent must store
the 'next available event number' value across
re-initializations of the system, resetting it to 1 only when
the configuration is reset to defaults.